I think they can be helpful if used properly. That means not just blindly following the most popular moves if you don't understand why they were made. It's better to make a sub-optimal move you can at least grasp the ideas behind.
A good thing to do I think is to try and analyze the position just by yourself 1st and come up with a move before comparing your move with the choices from the database you're using. Also, if there are several good choices to choose from it may be a good idea to search deeply into all of them to get a better understanding of which one you prefer.
What's your own opinion in the use of databases, like the Game Explorer - while playing the Opening of your game?
If we use databases, do we cheat ourselves of the value of learning the game?
Or do the databases enhance the learning process?