One day you wash up on the beach, wet and naked. Another day you wash back out. In between, the scenery changes constantly.
So, what's the advantage here? Less foam? Faster fill? It is pretty cool. :)
Filling faster, because of the lack of foam, is obviously the commercial advantage. The video shows one person essentially filling 4 simultaneously. You can't do that by hand, especially when you have to wait for the foam to settle. Now, at home, leaving more carbonation in the beer leads to better burps.