I didn't get a spare wheel at all with my car. I got 'run flat' tyres. And they work well, in that they let you get home or to a tyre repair/replacement shop without needing to change the wheel.
I'm still not quite convinced though. It seems that the fix is often not to repair these tyres, but to replace them. And that is more costly.
New article, but haven't we been seeing this technology get occasional PR for years? And yet it never seems to get anywhere (no pun intended).