Cash has been replaced by cards but in some countries like china cards are being replaced with qr codes scanned in via a mobile. This is where bitcoin payments are going to be done in future
exactly, the celphone itself becomes the card, Do you think it's dangerous when all the money is in the same card, or do you know that the phone you're holding in your hand is very vulnerable
In my opinion, bitcoin should still be on the encoding of other devices than that.