Having played a few of these, yeah, you hear it a little better as the player. They don’t sound that much different out front.
If you think about it, on an acoustic guitar the top of the guitar is the “speaker”, driven by the vibration of the strings through the bridge. That thin plate drives vibration of the air it’s in contact with on both sides, front and back. The vibrations from the front are desirable, because you want the audience to hear the guitar, but the sound projecting back is only useful to the extent you can reflect and redirect it with the body cavity and sound hole(s).
So yeah, to the extent that sound coming out of the side of the body is useful, these make a difference. It’s up to you if that’s actually important to you though. IMO these are less useful for performance situations, more for people playing for themselves (practicing, etc.)
The SSA has a great site showing projections into the future of various proposed modifications. That plan specifically does not on its own solve the problem completely (though it does help, extending the time frame for exhaustion of the trust fund out to 2060 or so). If we wish to avoid the exhaustion of the trust fund, we’ll need other measures as well.