I've purchased two sets of
I've purchased two sets of new MINI wheels and tires locally on Craigslist. The last set of new 18' wheels and tires cost me $600 for 4. Now I have 8 wheels and tires with Run Flats for summer and a set with Snows for Winter and a Mercedes collapsible spare with adapter in my Countryman just in case. Not worried about losing the car for days, but when the RFs wear out, they're be replaced with standard sidewall performance tires.
We do have a good friend who really has to have the Run Flats, but he's wheelchair bound and isn't able to change a tire on the side of the road. That's the only good use case I can see.