I would consider that VERY sophisticated. One needs to basically conduct identity fraud, so have enough information to port your SIM via your phone company. I imagine that if you do not call your phone company with your existing number they have a few extra steps to allow anything to happen.

Anyway, beyond that, which as you shared (thanks for taking the time to put those links) is indeed not infeasible (but still requires targeted work and skills) this is only 1 step out of 2 for authentication against a bank. One still needs to know the bank and the login/password pair the Website requires.

Even once that's done, I believe most banks do not allow large transfers, e.g. above 10K EUR, without another verification. Typically transfers have a daily and weekly limit that can be modified temporarily.

So... IMHO it's sophisticated (in the sense that a "script kiddie" or scammer without technical skills can't do it) and has limited economical value.

I will remember it (again, thanks for pointing it out) but I won't lose sleep over it.

PS: I'm wondering what's the consumer law on this actually because arguably some steps, e.g. no limit transfer or SIM porting would be on failure on the side of companies, not consumer. I wouldn't be shocked if companies had insurance for that and might have to pay back whatever amount would be stolen. Obviously this would be regulation dependent.