It's something that's been in development for some time now. The promo video is from 2005. Until it's actually available, there's not much more to say about it.
Maybe that's why they aren't on cars. I also wonder about the aerodynamic effects of something that probably acts like a fan impeller. Not so sure they're perfect. According to a wiki article, the tweel had 5% MORE friction than a conventional radial tire. We'll just have to see if/when they're offered for cars.If the accumulation of dirt, mud, and snow was a problem, Michelin would had tested that already, and maybe will either redesign the Tweel with those opening covered, or sell an aftermarket set of plastic covers to prevent the clogging.
I see this type of wheels perfect for EVs because they are lighter and can absorb road shock and noise better than the air-filled radials, in addition to being non-flats. If I had a BEV and could buy the Tweels for it, I will. And I will never get them clogged!