Family sharing, some clarifications needed

Recently we've set up family sharing. Now my SO has done an in-app purchase. So far no issue. But when I told her she was a little upset that there was no way to make the payment herself. Because obviously I got to see the purchase.

So, how can she pay for her own purchases, whenever she desires?

This article suggests it is not possible, except when using iTunes store credit or vouchers.

And will the receipts for purchases based on her iTunes store credit or vouchers also end up in my mailbox?

After all in many families there isn't just a single parent and then kids (in this context apparently handled as subordinates). It seems like this would be based on a view on the woman as stay-home mom with the husband paying for everything?!