Are the game updates mostly for online play ?

I have recently disbled my ps3 from going online, cuz I don't play online, and my games work fine without updating. So I am wondering what the main benefits are to game updates ?

I know that some updates incorporate move controls, and other updates fix small glitches etc, but is there any other reason that I should update my games manually, and if so, is there a list somewhere which outlines what the updates do excatly so I can decide for myself if I need it ?