I like it because you can think about moves for a while, enter themed tournaments where you get a better sense of openings, and play somewhat higher quality games.
For the opening database I haven't really run into problems as most of the people I'm playing at <1750 deviate fairly early on. Could see how that we be a problem at higher ratings though
I don't understand why people play daily games. I posted a topic similar to this in a club and the people that answered basically said "ya, daily sucks." I agree but I want to see the POV of people who play daily. Here is the topic I posted in that club to back up why I don't like daily:
I just joined the daily game tourney between us and the Southeast club. I've always kept my distance from daily for multiple reasons but decided to do this and only have these two games going. The main reason though is because of the grayish rules on cheating and not. Am I allowed to used the built in database for the whole game? If so then I could just follow GM level moves for almost the whole game but even worse my opponent can also. That just seems so boring. Me and my opponent will just be copying moves for the whole game and if I choose to not then I will get bulldozed. Is this really the case?
So, Why do you play daily games?
Unless you get into some line that has been played many times, you will run out of known moves by move 10-15 (sometimes before that). In most cases you will be on your own since late opening / early endgame.
For me, I like longer live games more. Daily can be used as a way to review opening lines you wish to play by using that inserted opening explorer you get as a separate tab in your daily game. Along with that, you have more time to think of some plan in an opening you are playing, which might be useful when you play a live game.
There are certainly downsides, you will not really train your visualization as you have analysis tab and can make moves on it. It is not a replacement for longer games, it is created to replicate the experience of correspondence chess along with its rules.
I know this post is a few months old, but my reason for playing daily games is simple, I have a full time job, family responsibilities, etc. that doesn't allow me hardly any time to play much rapid games. I hate blitz and bullet games. Playing games that are 5 minutes or less to me is not true chess. I like the longer games where you can think and strategize. And I set my rapids for at least 30 minutes per side. Usually, I am only able to fit in a rapid or two after wife has gone to bed and I'm still up at midnight.
I don't always have the time to sit and play a full game. I also like waking up and seeing all my pending moves so I can get my day started with chess
Is it a sign of how entertainment has developed, to satisfy a demographic with an attention span of ca. 7 seconds? This new, younger demographic loves the excitement and speed of Blitz and Bullet, but can't find the concentration to look in to the subtleties and complexities of positions.
I rarely play Blitz, as I find it unsatisfying to move according to memory and reflex, as in some shoot-'em-up, kick-him-in-nuts video game. By having ten daily (24 hour) games on the go, there's usually someone awaiting my attention and, depending on the time of day, we may play six or seven moves in the same game in quick succession. I also play thirty minute Rapid, which I find a decent compromise between the two extremes.
P.S. Yes, I am a boring ol' phart! 
As have been mentioned, with a full time job and family responsibilities, daily is the best way to play a quality game. Blitz and bullet may get adrenaline going, but leads to poor quality of play. If the pace of game is going to slowly, then you take on a couple of more games until it feels right.
How exactly will you get bulldozed if you decide to vary from a GM game? Is your opponent a GM? Does he have access to some GM's published treatise on "What to do if your opponent DOESN'T play 12. ... Nc6 in the Advance variation of the Fischer-Sozin Najdorf"?
If you vary from established praxis, then your opponent is thrown back on his OWN resources.
To answer your "Why Daily?" question... some people like to make GOOD moves, instead of playing the "Who can blunder the most times in five minutes?" game.
I moved to daily games awhile ago. I need more time to mess it up. Lol. That and I found better sportsmanship in the daily arena. The day time gig is full of time constraint stress, the last thing I need is more of it!
People that play to compete with other people and prop up their ego, talk trash, etc. generally prefer blitz and bullet. But you can get that feeling from a ton of games...I'll be happy to school you in QuakeCTF if you disagree 
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People that play to compete with themselves and play beautiful games of *chess* without blunders galore play daily.
Just my opinion.
This is why daily is so great...and why playing votechess on a really good team that has discussion every move is awesome...
- You learn the openings you play much deeper, and you can play out lines by various masters and see what types of positions result...for example, pushing e5 which you thought was "aggressive" but you then see allows black to lock up the pawn structure entirely, etc.
- You learn where the big positional/strategic decisions are (do I advance e5 and lock the center? do I trade off my bishop for this knight?), and more importantly, how to evaluate them to fit with your strengths
- you learn to pay attention and play more accurately in endgames, a skill sorely lacking in blitz and bullet players that are usually scrambling at that point
Just be careful...do engine analysis *after* every votechess game and get off the team if they start to have a T3 match rate of 70% or higher. You can usually go back through comments and figure out who is using "assistance" (always picking right moves but can't explain well why those moves are good when promoting them, etc.), but not always. The "top" votechess teams *all* have high matchup rates (sadly), so find a "boutique" club with admins committed to keeping the club clean.
I don't understand why people play daily games. I posted a topic similar to this in a club and the people that answered basically said "ya, daily sucks." I agree but I want to see the POV of people who play daily. Here is the topic I posted in that club to back up why I don't like daily:
I just joined the daily game tourney between us and the Southeast club. I've always kept my distance from daily for multiple reasons but decided to do this and only have these two games going. The main reason though is because of the grayish rules on cheating and not. Am I allowed to used the built in database for the whole game? If so then I could just follow GM level moves for almost the whole game but even worse my opponent can also. That just seems so boring. Me and my opponent will just be copying moves for the whole game and if I choose to not then I will get bulldozed. Is this really the case?
So, Why do you play daily games?