We keep the good bikes downstairs. In the basement. It is a royal pain carrying them upstairs. That makes us do more miles because it's not worth it to drag the bikes up for a wimpy ride! My biggest reason is that I don't like spiders, and the only option is to store them in the barn with the spiders. If one got one on me when I'm riding I would crash!
We have some crappy bikes in the barn, and I would still be mad if someone got them. But they'd have to fight with the spiders, snakes, rodents and wasps, and my dog barking.