Short answer is all that advice is obsolete. Biometrics as used by secure enclaves have tradeoffs which are unrelated to the (again, obsolete) practice of storing biometrics as authentication per se.

The secure enclave holds biometrics, these are used to generate ordinary key pairs which are revokable.

If you have a device like this, try it! Register a finger, then un-register the finger: congrats, you've changed your fingerprint.