If I said continents, then that would make sense. I didn't. I said regions. As in, a specified territory of land. The areas I specified in this scenario being that which is known as Europe, and that which is known as the USA. Regions. Comparing the same type of things. Not "apples and oranges."
If you want to forget geopolitical differences between a country and a whole continent, so yes, they are comparable. Now let's compare my backyard with the US. What, they're both specified territory of land, so we should be able to compare!
I didn't want to drag this flame war, but oh well...