The first map you see is the whole world including North America, @Carrie454, and the other maps are for places you're not in. If you want to stay in North America, type in a place name, a state or a city or a river or something. Or go to a category, choose "map," and center it on the US.
But you asked why, not how. I don't know, but I guess it has something to do with imagination, bucket lists, destinations, hopes and dreams - whatever marketing gurus think leads to that be-all and end-all called "engagement."