Why do Americans have many pillows on their beds? 为什么美国人床上有那么多枕头

They are pretty and make you rooms look cozy. I love seeing your room tour, especially your bedrooms. But wondering where do you guys put these pillows when you sleep? Do you just sleep with them? If so, don’t you feel the space you can sleep on is too small? If you put them on the ground when you sleep, don’t u feel they would get dirty? 美国人的床铺布置总是很温馨，很多漂亮的枕头是加分项！但是睡觉不难受吗？睡觉的时候把他们放在哪里呢？