Not everything in the game needs to be useful, important. I'd like to think that games could include aspects which are purely there for if you want them, with no reward except you "yay, I can do that". Little things like this could (and I say could cause I have never been involved in the development of any game) go along way to increasing immersion and realism, in my opinion. It's not everyones flavor, I'll agree with that, but food for thought.
With that in mind, you just have to wonder whether time spent developing that could have been better spent making other things. There are games that cater more to "mundane" aspects of life, like the Sims, but Skyrim is an Action Adventure Fantasy RPG. Unless it's the most epic dust sweeping in the world with lives at stake, I don't want to consider it. This genre exists to replace the boring parts of everyday life, where you don't need to worry about things like keeping your personal belongings clean, whether or not you have a cavity, or if your armor is getting rusty. If NPC's want to do it, that's fine. They aren't protagonists, they don't care about being boring peasants. I just don't feel like playing a game where you're a boring peasant, it lacks excitement.