Someone already said it best. I do it because I don't have a choice.

I leave home for college at 7AM, and get home anywhere between 4PM to 7PM. Accounting for homework, food and sleep, that really doesn't leave much time to try and destress a bit, and I DEFINITELY don't have 5+ hours to spend TRYING to log in.

I refuse to log out until I know for a fact I'll be able to log back in when I actually want to play, and I can't blame any other AFKer who does this.

Square has made it become a necessity.