Family sharing payment

Why the **** as a parent can’t I use my own payment method to buy apps or in app purchases when in family share. why do I need to use my wife’s details this is a use less feature. So apple have a family share which is great but for me to use my own payment method ie PayPal I need to disconnect from family share to use it or pass it all on to the main organiser. Why apple seriously why!!! Bloody useless!!!

all I want to do is family share my purchases and be able to use my own accounts to buy New things!!!!