The more payment methods, the better. Although, I don't think that anyone is going to buy with bitcoin currently. You realize that he/she has to pay product's price + ~$7 in order to get the transaction quickly confirmed. If the fee was much lower I would suggest adding it.
It's on the buyer if they will purchase the item on online with bitcoin because the buyer will automatically provide the gas fee. I don't see any misuse on his/her statement. It can be an investment beside on having already a business.