Because everyone will have the same hardware then and everyone will have the same conditions.
Then Onlinegaming is more fair.
Additionally, you will not invest as much money,
because consoles are cheaper,
nowadays just a graficcard costs as much as a console.
Concerning FPS, they just need to enable mouse and keyboard-support. Strategiegames, MMorps and racinggames are already playable ...
They should also add some VGA-Output to monitors,
for the more serious gamers.
I also think that IRC, ICQ and Web is possible on consoles ...
Maybe by some Communications-CD ...
it may also be possible to run the pc simultaneously ...
and then just switch over to the console, when you want to game (maybe even with some Video/Mouse/Keyboard-Switch-Hardware).
I just hope consoles will take over onlinegaming,
cause then everything gets easier (because of standardized harware) and more fair.