I have heated seats in my fiesta and I've used them about twice in 18 months. The car before was a golf that also had them and probably used them as many times.
I would never 'spec' them. They just happened to have them and frankly never used. Surprisingly enough I find the same with cruise control. Most of my cars have had or yet hardly ever use.
I imagine BMWs will be just the start. Once it catches on then other dealers will no doubt follow suit.
You'd be lucky to get a new car. My mate ordered one in October and it was due in May. It's just been put back again for the 2nd time. Apparently 99% 'made' yet waiting on a couple of electronic chips or boards. Probably the same place as the PS5 ones
.