We always use our AX card when possible. They are great to cancel or hold any dispute you may have and if you lose your card or some other tragedy they are super quick to make it right for you! They also provide excellent details on one's spending so it is easy to calculate for trips, taxes, etc. If you lose a prepaid card.... well.... and debit cards don't have the security that credit cards do, one can cancel a credit card, but a debit card means you might have to close your bank account...especially if it is stolen or lost!
We always split our cash so both of us have cash in case we need it, that way if one loses a wallet at least we have the other...
With all that said we have never lost a card or cash when traveling, misplacing things at home...now that is another matter!