Not sure if anyone knows this. But PS3 supports mouse and keyboard for games. The only game I can think of that has used it so far is Unreal Tournament 3(or was it 4? so many of them).
My top 5 reasons.
1 better hardware.
2 scalable graphical settings.(I was playing WoW last night with my friend. She could see monsters at a further distance then I could, because she had 1/3rd the amount of plants as i did.
3 Mods. Mods are fun. I wish my PS3 games could get them.
4 Alt+Tab. Seriously, I sometimes need to look shit up on the internet. Much easier if all I need to do is alt tab.
5 Lastly, Higher resolutions if you want it. Makes things nice and crisp.
EDIT
6 Emulators!(completely legal if you already own the game/system and don't want to get it out of the attic!) I cant tell you how many times I have enjoyed old school genesis games on my PC.