Sending everyone all the prices is literally the dumbest thing you can do. But the combination of a small payload and universal prices scales to millions very cheaply. In fact, because of our infrastructure, for the foreseeable future, the more people who use the app, the faster non-Tor refreshes are. It scales to millions of users very cheaply. And it's the very thing that enables users to verify the server isn't getting personal information through price-fetching. It's a kind of rare case where the dumbest thing also just happens to be the fastest and most private.