> There is absolutely no reason for Discord—a chat application—to run everything a browser does

Chat apps are literally the central example of why Electron is a God-sent. Here's a video from a Rust guy explaining why there are quite a bit of reasons to do it https://www.youtube.com/watch?v=hnaGZHe8wws .

You don't need a full browser-engine just to render some text with images. The majority of the web api sprawl browsers implement is just baggage for that.