What’s with the rugs?

Why do people put rugs on top of carpet? It seems a little counterproductive to me. The point of a carpet is for it to be soft on your feet and be easily cleaned. I guess it would make more sense to put down carpet on top of a rug if you had small children that spilt a lot of things onto the carpet. I think it just looks tacky. There is already a carpet there so why waste the money to put carpet on top of it? It might be a good idea if you live in an apartment and are trying to prevent permanent stains. It also might be okay if your carpet was really ugly. I guess I will never understand some people.