Why? Because they like to think about thier moves a bit longer rather than shuffling? LOL
Standard rating > 400-500 from bullet/ blitz? Computer cheater?

Probably not. I have a higher online rating than my live rating because, well I can think longer and can use the analyze board. I have a incredible low rating at bullet and blitz because well... I just can't play fast. Even the 30 minutes games are too fast for me. I need 45|45 at least... else I'm done for.
Then again, I never play blitz/bullet, I can understand why people like it, but to me it's another game. It has an awefull lot in common with chess, but it's just not for me. Suck at it, don't like it, don't enjoy it and can't learn a thing from it. Except anger-management maybe.
I keep playing people with standard ratings >1800 yet they can't seem to manage a 1300 bullet or blitz rating.. are these guys cheaters?