I'll answer that question using myself as an example:

I have account in my country banks, but my country's banks only allow people to deposit money into their accounts if people give income statements... as bitcoin is not legalized in my country so I can not deliver the income statements that proves the provenance of my funds. I can use paypal to withdraw my money for my bank account, but I can not withdraw more than  $1000 from paypal to my bank account.

So with mastercard card i solve my problem. That's why this idea of @OP is very good.