I’m still waiting for an answer from Starling Bank about why their debit cards (or at least mine) store details of transactions on the card. This data can be read with a mobile phone and free card reader software (and presumably contactless terminals in shops).
It doesn’t overly concern me, but maybe it should. Someone on this forum said that maybe it was just a default setting they didn’t turn off. Maybe @Rika knows more about this from a Monzo point of view and whether that sort of functionality is default, or whether they decided to turn it off for Monzo debit cards?