In Sweden where I live you need to use the digital national ID whenever you make a credit card transaction via some app, for example when buying a bus ticket, so you need to have it with you at all times. But with the ID you can also take a quick loan and transfer all the money to a foreign bank basically ruining your life as the bank take no responsibility if the ID is used during the transaction.
Does the app not require authentication? At least MitID in Denmark requires a 6-digit PIN at the very minimum, or biometrics optionally.
To help slightly I've set my username to a long string of random digits.