Just ask, don't push it, if they want fiat give them fiat just ask them if they know about Bitcoin and make sure you don't fuck them.
But what OPs pointing is for bitcoin to circulate and be used on what it was created,the problem in bitcoin bow is being considered as asset and investment not a Electronic money to be used for payments in any transaction over internet
But you have a point to,because if the person dont know how to use bitcoin it's nonsense paying them with this instead use physical money for what is applicable