Lot of times I want to chat someone specific if I have a question or an opinion to get. Sometimes someone has a question I want to answer. This just helps quickly figure out if someone you want to talk to is online or not. There is a social aspect to this game…not everything is centered around scores and points.
But I suppose not everyone is going to be comfortable sharing that online status. My suggestion would be allow users to configure that as a privacy setting to stay invisible.