Besides the obvious of how quiet they can be made.
I'm really into dual use kinda things. That's why I like switch barrel capability of the savage Savage rifles, quick release throw levers for day optics, night vision that I can move around, etc.
Well the ability to talk a popular military case (.223) and size it to take a popular military bullet (.308) to make this setup run is uber cool to me.
So not only will I have a rifles that will chamber our military calibers, I'll also have a barrel to put on one that will handle a round made from components from each, that will perform admirably either supersonic or subsonic. Totally Awesome. Now I just wish I was made outta money
Paul