Is it though? Worst case call road side assistance and what an hour or two. Now if you live in the back country, okay, but for the majority of people it’s just an extra 40 pounds to lug around to use once or twice.
Actual worst case, you're stuck on the side of the road god-knows-where, for god-knows-how-long, hoping that someone will drive by and have the decency to stop and help.
I think I'll buy a car with a spare tire.