Yes, i do and i've 2 cds of java games from mobiles. but i don't play much cause most of usage is to read some PDF booklets.
Yeah, Hmm.. because it's convenient way to kill time when your travelling or far away from any game consoles, computer or portable consoles.. I have a GBA emulator in my n6630 phone which I use to play GBA games mainly RPG
I bought an iPhone originally because of my long commute on the train to work, the idea being to watch videos etc (which it is great for by the way). But I also found myself buying a lot of games on it, my favourites being Peggle, Bejewelled and Angry Birds.