I can't imagine anything less interesting to me that playing those games on my television.
So when you already have friends over at your home, what do you drag out to do for fun? Taking turns in a single-player game on a desktop PC isn't very fun, and asking them to drive home and go get their gaming laptops isn't very practical. Playing games on a PC hooked up to a TV is much more spontaneous than a LAN party. Or would you claim that video games are for one player and tabletop games are for two to four?