It is not anything new except the bow part. All that is is a bang stick using an arrow instead of a pole. Scuba divers have been using those things for decades. They wouldn't be legal in PA now and I don't see them as being legal any time in the future.
I can already here the posts. "So there I was. Only shot I had was right up the exit ramp but I knew my new (enter current trendy favorite bow) and my exploding rack em back broadheads would do the job every time. When the broadhead exploded it sounded like a wet cannon. Splattered guts all over the understory. Made for a short tracking job and a butcher's nightmare but hey, I got him, right?"
Know a guy who found some old hollow aluminum arrows and realized that they could be filled with powder and a shot gun primer fit snug in the front end. He was shooting the things against a brick wall and thinking it was great fun, till his prize hunting dog got cut up with shrapnel. Bubba is as Bubba does.