Do origins matter? Well, sort of. I do like to know whence they came in case anyone asks, but how many people in an audience are listening to the words well enough to wonder where they came from? So, who are you introducing the song to, other singers? Let 'em do their own research.
I prefer the Vin Garbutt approach to intro's. I defy anyone to listen to his ridiculous dissertations (Not the right word, but I don't know one) and wonder about the origin of the song he's introducing. You are too busy listening for where the gorilla comes in..... But you will be listening, and probably trying to understand the accent.

I wonder if American culture IS replacing indigenous ones. American TV programmes and films are, but how typically American are they? Escapism, mostly.