The question is how well know the alt coin is. It will depend on the rank of alt coin, the usage of the alt coin. If you want to use only a specific alt coin, that will be a problem for your customers. If you allow multiple coins, that might be a good choice. But let's say you offered them your products that can be bought with Elon coin only at this moment, surely customers won't buy elon coin just to buy your product unless it's too important. Moreover, most of the cosmetics they can buy with fiat and other currencies. So, they won't take the hassle.