I don't think it has worked, it doesn't mean it doesn't work. we know that market movements are very fast affecting the value of the crypto aser. I think this makes crypto unable to be used as a payment instrument. but there are some that have implemented it, maybe new bitcoin and ethereum are accepted.
There's some payment gateway out there that gives the fixed rate when the client is about to purchase with bitcoin therefore preventing fluctuation that could happen when the transaction was made.
the money then will be sent to the seller's account in form of USD not cryptocurrency anymore, guess that solve the problem.
Yes, ideas like this help address the price volatility problem.