While it might be fast, it feels you’re like using Rails app with turbo links. Page loads. Feels barely interactive.
Compare native Mail app and Hey. If anything should be a SPA, it’s an email app.
Also who cares how much kb of JavaScript your mail app uses? It’s completely wrong metric to optimize for an app someone uses every day, multiple times a day and likely has the app open all the time.
(Also haven’t heard people using Hey much since the launch)
If Hey is a toy app you then you must be working on some truly alien projects from the future or something.