Why do I need to use a credit card or debit when I’m not making a purchase.

Hi there,

You won't be asked to provide card details as long as your payment method is valid or set to None

Change, add, or remove Apple ID payment methods - Apple Support

Do not add directly your card details, iOS apps won't ask for it

Provide specifics

A

A card is only needed to make a purchase.

It is not used to log in to anything.

You need a payment method if you are downloading an app that has in-app purchases.