Is it possible to make a system where I tap my bitcoin debit card on a POS terminal and transfer BTC to a merchant? I'm not talking about something like a BitPay card which converts BTC to fiat and uses traditional payment processing; I'm talking about using the bitcoin network so that the transaction is in a block ~10 minutes later.
Hypothetically speaking, how would this work? The card would be provided by a third-party service, is it possible to have this and still be in complete control of my keys? How could my tap on a terminal lead to a bitcoin transaction that's broadcasted through the network? Would you need to pre-load keys and addresses onto the card, or could the tap somehow authorize the card company to transfer the bitcoin ownership (I can't see how this is possible if they don't have your keys)?
Are we better off just using smartphones and other devices for transactions?
It might be possible somehow in the future? I guess there are some people who are working on it right now for it to make into the public? As there are only few stores that acveot bitcoin as a payment I think it won't gonna work.