The Computer Analysis has no idea what it's talking about

1. e4

1... c5?!

INACCURACY - Perhaps better was 1... e6

HOW???

Its very much like Tactics Trainer. If i do a mate in 4 instead of a mate in 3, they consider it as an inaccuracy.

The computer on chess.com is faulty. Consider analyzing your game with an engine such as Rybka or Houdini. 

Actually, I believe if you play a mate in 4 instead of a mate in 3, it says you made a blunder. And yeah, sometimes the analysis is completely faulty, and when it is not, it may be shallow. In short, it is a very useful tool to check if you or your opponent missed any obvious tactics. Other than that - use Houdini.

I'm fully aware that opening analysis isn't as effective as in a tactical position, and also that better methods for analysing exist in the first place. Rather, I just found it funny that Chess.com's analysis engine (Premium version too, so 2500 strength, or so it claims) seems to think that the Sicilian Defence isn't accurate.

Maybe it knows something we don't... 

same here. I played the sicilian and it reccomended the scandinavian.????????????? And it gave the line

I don't understand this...when I play any book opening at all, even something highly unusual, it just says "book move" and doesn't give any plus minus or recommendation....