Why can’t I make payment with my Apple account balance

This document outlines what you can buy with your Apple ID [Apple Account] balance --> What you can buy with your Apple Gift Card or Apple Account balance - Apple Support

"Some purchases might require that you have a credit card on file, even if you use your Apple Account balance to make the purchase."

"Where the Apple Gift Card is available, you can use your Apple ID balance to buy products and accessories at apple.com or in the Apple Store app."

How apps, content, and subscriptions from Apple are billed - Apple Support

Some purchases aren’t charged to your Apple Account balance

- If you're in a Family Sharing group, purchases that you make are charged to your personal Apple Account balance. If you don't have enough Apple Account balance to pay for the purchase, the remainder is charged to the family organizer if purchase sharing is turned on.

- You can’t use your Apple Account balance to buy gifts or gift cards.

- Some subscriptions might not be charged to your Apple Account balance.