Is carrying around cash in Iran is the best solution for foreign tourist?
Actually, Iranian debits card is the best payment method in Iran for some reason. Besides the risk of a lost or stolen a bulky wallet, sometimes, there is a problem of changing the high-value denomination bank notes because they ran out of the change and you are asked to pay by card. So the Answer is No.
We suggest getting your Iranian Debit gift card to avoid getting into trouble. Payment by Bitcoin is possible.