In quick summary, it looks like a large, built-in U-lock with the frame itself forming part of the U. Not un-stealable exactly, but rather a deterrent in the sense that using traditional U-lock-breaking methods like a carjack could damage the frame making the bike worth less(or nothing).<p>You'd still need to secure the tires, though, too. I can't tell if there is a built-in part of the U-lock that allows for threading a cable through or anything like that. Typically what I see is something like U-lock around the rack, front tire, and frame with a cable threaded through the U-lock and through the back tire. Not invincible either, of course, but much more work and therefore more of a deterrent.
That bike seems more stealable than the folding bikes I used for commuting before I started working from home. Interestingly, during all the years that I used folding bikes, I was never prevented from carrying my bike into a building or onto a bus, etc. (Though, I did need to cover it with a bag before placing it in shopping carts at grocery stores.) It worked out amazingly well.
The premise is that thefts involving frame breakage would be lower: this is not necessarily true. If the components are nice enough then it is worth the thief's time to break the frame.