They all do this now, to one degree or another. [1] [2]
The economics are even worse (because they don't get a cut from the restaurant), so these types of orders are either very high fee for the consumer, a loss leader, or both.
I don't actually think the celebrities are contributing purely out of an altruistic desire to 'give back'. I think that's _great_ marketing by Masterclass, but the primary thing celebrities get by associating themselves with Masterclass is helping continue to build their own brand. Masterclass has positioned its self as "the best in the world teaching their craft", so by agreeing to be on their platform a celebrity is getting publicity that reinforces the idea that they're the best in the world at that thing, and that they're still socially/culturally relevant.
https://bit.ly/3gEqOkw
(bitly link, because the URL specifying the search filters is unreasonably long)