Mainly, the benefit is the interaction. Cip wanted to go futher on the "social network" interface of the game than just see who is online or not. You can have friends and colegues on a list where you can check related characters, even in another world, they account and character's status.
I know it seens a little "useless" now, but that definitly opens a door for a whole new spectrum of utilities in the future. Like you use this list for direct interactions like party/exiva/healing/trade or even a inter-worlds chat.