Thought for the day: Player Housing

Wolfshead makes a passionate argument for player housing in World of Warcraft. The problem I see with the idea is that Azeroth is a pretty tightly populated world, and there is no way it could support 10,000+ player houses distributed all over the existing world without looking utterly ridiculous. Thus player housing in WoW would necessarily be instanced. Which means nobody will see your house. So what would be the point of having player housing? What exactly would you want that house for, and what exactly would you want to do in it?