I have a balance in my apple account, along with the required credit card. My streaming purchases are charged to my credit card, rather than my account balance. Information tells me the account balance will be used first.
Apple TV 4K, tvOS 14
How App Store and iTunes Store purchases are billed. Click here --> https://support.apple.com/HT201359
"Some purchases aren’t charged to your Apple ID balance
- If you're in a Family Sharing group, purchases are charged to your personal Apple ID balance. If you don't have enough Apple ID balance to pay for the purchase, the remainder is charged to the family organizer's primary payment method.
- You can’t charge gifts to your Apple ID balance. If you send a gift or gift card, your primary payment method is charged.
- Some subscriptions might not be charged to your Apple ID balance."
Maybe the last line?
apple store balance
