I wasn't trying to buy a new number, I was trying to transfer an existing one. It doesn't surprise me that they make it as easy as possible to get a new one.
Either way, it's the behaviour of a crappy network rather than an issue with e-sims as a technology.
Not that that's unusual, most of the networks are crappy - vodafone was the only UK network I could find that didn't require you to go to one of their stores to get the QR code. Artificial barriers are erected at every turn.
I wasn't trying to buy a new number, I was trying to transfer an existing one. It doesn't surprise me that they make it as easy as possible to get a new one.