Educate me on rim blow steering wheels

A lot of '71 Darts had them. They weren't available in '72, so the theory goes that they just put them on just about everything in '71 to use up the remaining stock. My butterscotch GT has one, and I suspect my other GT had one as well given that the steering wheel had been stripped from it when I bought it.

The originals go for a pretty penny, and restoring one is WAY pricey. After all of that, they rarely work as intended, the rim blow switch is very finicky.