This could really work out only if the owner will get the perfect balance of bitcoin and fiat payment. In a business, most particularly with stores that offer products, the owner is required to restock so that the customers can have a wide variety of options to choose from. If most payment would be in crypto, he won't be able to buy immediately the things needed in the store because he first have to exchange it.
Hence, it should be balanced. Or at least have a margin for every bitcoin payment so that you won't be the one losing if ever you'll have to pay for transaction fee for converting it back in fiat. This will also serve as your bounce back if ever bitcoin will suddenly decrease in price.
You could always have USDT or BUSD or any other stablecoindireclty converted system? I mean that way the owner would be able to accept 100+ different coins, which is awesome for the offer, and I did it, I accepted 100+ different coins when I was selling something. Then what happened? I just clicked a button that said "automatically convert to USDT" and that was it. Then I was able to pay the person I got the item, buy more, and resell it again and again.
Turned 1 item that I bought into 73 of them in my hand at some point, without spending a single dime, all paid by the customers I sold to, all automated converted into usdt. After that I stopped and just got rid of the inventory for very cheap and went back to my original job which is writing, and I love it.