Sub-accounts

How important is the idea of posting in character with a dedicated sub-account (complete with avatar, maybe even post history) to you as a player. Do you feel that it is too much immersion, or would it get in the way of game play, or become too confusing for other people reading the game? Or do you prefer it because it's easier to keep track of which characters post in a game, feels more authentic, etc?

I'm considering getting a sub-accounts modification for my forum, but I'm hesitant. What do you think?