Would it be "good" for self-defense? I wouldn't volunteer to be shot by it.
To put it in perspective, the video in Willie Lowman's link showed 2,994 feet-per-second out of an 11.5" barrel. Taking a pure guess, can we say maybe 3,200 fps out of a 16" barrel? If we go with that, the muzzle energy is 1,024 ft-lb.
For comparison, the 55-grain M193 that I carried and shot in Vietnam has a muzzle energy of 1,294 ft-lb. The current 62-grain M855 has a muzzle energy of 1,371 ft-lb. So the varmint round is giving up a bit compared to the military stuff. But a lot of people are perfectly happy with a 9mm pistol for self-defense. The muzzle energy of a 115-grain 9mm is 355 ft-lb.
So the varmint round has plenty of energy, and it's pretty clear that all that energy is going to be dissipated in the target -- you're probably not going to have to worry about over penetration. So then the question I would be concerned with is how well it would perform through clothing. It would be interesting to see a video of this ammo being shot into ballistic gelatin through a couple of layers of denim, for example. It would also be interesting to see what happens if it's shot at a sheetrock wall. If it fragments when it hits a wall, that's a positive attribute for a home defense scenario.