Meh, I've seen a few of these pop up and get articles written about them over the years. They usually disappear soon after. Probably just trying to scam money from Investors.
I read on a pop sci magazine years ago that "this is not the first time we have offered a design, but nobody was willing to buy one so it didn't get built"
Unless it's a nuke sub that lets your rich ass just disappear under the water I don't see the point. Cruising around under the surface with a snorkel up on diesel engines just seems like a straight downgrade. Why even go out of your bunker.