You asserted that since Crumbl sold a lot, that was evidence it tastes good. They provided a counterexample of food that sells a lot and doesn't taste great. You pointed out that McDonald's sells because it is cheap and fast like you think you made some point for your argument, but you actually just confirmed his point that food can sell for reasons other than great taste.
Crumbl, like McDonald's, sells a ton, but neither sell a ton because of great taste, but for other reasons. In the case of McDonald's, it sells for price and convenience. In the case of Crumbl, it sells for presentation at events. Crumbl knows this. If you ever try to be one of their franchisees they will straight up school you on it. They are all about how their product will look for parties and celebrations because people love to set out these big, beautiful looking cookies, even though they don't taste that great.