I've never seen it either and it seems like this is very difficult to make happen. buying soda or snacks with bitcoin or popular crypto such as ETH or BNB is very difficult to realize because the prices fluctuate and there are still few people who know about crypto. buying things with your favorite crypto is much more difficult because it is likely that everyone's favorite crypto is different.
Can implement as payment in multi networks because everyone has personal choice to make payment in their favorite coins, like if we buying soda or snacks and we have only two option as like Bitcoin and Ethereum, that's really difficult to many peoples, because transaction fees will be higher than your buying products price, so need less fees payment method.