There are lots of reasons, many of which I've written about here. Tonight provided yet another.
A young man just enrolled in my class. He is very polite, very tall, and very Chinese. With my many Latino and Russian students, it's always clear to me which are first and last names, but with Chinese and Vietnamese students it's harder to tell. When I asked this fellow which name I should address him by in class he said, "Call me Paco".
I love that.