Better question is: Why would anyone but a sims dlc for skyrim? Why not just play sims instead?
It's a pretty silly statment.
Elder Scrolls games can be about anything you want. Some people collect things, some people like creating cool screen shots, some people scour the countryside for mats for crafting potions.
If an elder scrolls game is supposed to be "a world' then what better way to feel immersed than to have some actual tie to that world. This just adds depth to the game for those who can appreciate it.
And considering there is already house buying and addons to these games, this just takes it to the next level.