There is actually more a second MFA provider that is accepted almost everywhere, including the tax authority. I forget it's name and I've never tried it, so I can't say too much, but presumably it provides similar functionality as BankID

There's also swish, which is instant payments to both friends and businesses. Swish also uses BankID.

BankID is also used to sign documents, file taxes, etc.etc.

Swedish society is largely built around this one official MFA solution, and having a phone where you cannot run it is a real hassle