It’s mainly for Windows support, with the side benefit of being able to potentially extend to browsers (with WASM). Electron doesn’t run on mobile as far as I know.
I looked at a bunch of cross-platform UI toolkits, and everything has its tradeoffs. Qt is probably the most full-featured alternative, and I’ve had experience with it in the past, but I didn’t love the idea of tackling a project this size in C++. On the Rust side, Tauri is very promising but it’s still early days.
Aside from the framework, the other big tradeoff is 1 app vs multiple - more “nativeness” for a much slower feature velocity. The big companies like Slack and Figma don’t even make that trade with millions in funding… and it seemed unwise to take that on as a solo bootstrapped developer.
In terms of stuff like ecosystem, building/packaging, updater support, and even nice little native details like progress bars on app icons, Electron has a lot going for it. The big downsides in my mind are startup time, baseline memory usage, and disk size. Once it’s up and running, IMO app performance is almost all down to the app’s code. So I’m optimizing where I can - being mindful of algorithms, avoiding memory copies, trying to keep things cache-friendly, avoiding heavy JS stuff, taking copious benchmarks, etc.