Well, not in any way during the storyline, but in R/B/Y, it is used to hold a bonus Potion for early use in the game. It helps give a good headstart for the game.
In G/S/C, the computer in your room stores items and can be used to set up decorations in your room. It doesn't change the game horrifically, but definitely makes YOUR room look cooler than your friends'. ;)
In R/S/E, it does kinda the same thing, except you can only set up dolls, and in a small 4x4 space (The room's red-orange mat)
In D/P/P, it doesn't do anything special.
In HGSS, it does the same as in the originals.
