I would expect certain group of customers will go for it because of its premium look and feel. Those people are the ones who don't mind getting a 2nd or even 3rd phone--all premium ones--and picking one for every occasion. But for those looking to use it as their main phone, I highly doubt it will sell well.
They could buy the Air and another iPhone model, then tether the Air to the phone which has a physical SIM in it. In China, this is the sort of thing that happens 😁