Spain is weird like that. You've got to produce passports, proof address and have all that photocopied to get a prepay SIM.
It was easier to get one in China!
Where as here in Ireland getting a SIM works like this: Hello! Can I have a SIM please? ... Here you go... Would you like me to top that up for you?
Aspects of Spanish bureaucracy seem to still be a throwback to the dictatorship era. It's odd as they're really, really laid back and liberal about most other aspects of life.
You'd probably still have to do all that to activate your Apple virtual sim.
It's to do with not allowing you to be anonymous online or on the phone, nothing to do with the technology or the shops.
Subscribing to a domestic ISP requires your passport or Spanish National ID number too.