Yeah, so, like, the same as contactless credit/debit cards, only it can run out of battery

Yes, in Canada virtually every major bank issued debit or credit card for the last several years has supported NFC. There's different branding depending on the card - Interac Flash (debit), visa paywave, etc. But all use the same terminals.

No PIN, tap and go, no batteries.

With little user benefit, I'm assuming banks are reluctant to sign on to give apple a cut.