Imagine you have 3 credit cards linked to one bank account, now when you want to send all balances in all 3 cards to your friend's card, what will your friend see? as in, which one of your cards sent the actual balance?
This analogy does not apply to bitcoin, but if we were to use it it's still flawed. If you are making a bank transfer it does not matter how many cards you have, the receiver sees your bank details. If it is a card transfer, you certainly cannot use all cards at the same time, the card that sent it is displayed.
- Jay -