ASCAP for European Authors

Hey folks, I am considering to enter the US performing rights organisation ASCAP because they seem to have a couple of advantages. First of all, my local pro (GEMA) is not able to track youtube and other video streaming royalties at all. So I was wondering: How is your experience with ASCAP? Do they register and automatically pay for videos with their members music? If not, how do ASCAP members get paid if they have millions of streams on their music in videos?

Thanks for any information and have a nice day!