I won’t share it because it could be used to link my Lemmy account to my real life identity, not because you could use it to access my account.

Is this also not a good reason to not set up auto pay in the case of data breaches? Sure it may not be connected to your lemmy account, but does no other personal info about you link to that data?

It costs the landlord to take online payments

No, it costs the tenants.