I'm not super familiar with the space nowadays, but a few years ago cross-platform apps were full of compromises. Mobile apps wouldn't look native (tiny things like a being a pixel or two off) or they wouldn't support Linux. Maybe it's better with Flutter -- I've heard good things about it.

Additionally, Electron apps not only work as a standalone app, but you can often access a near identical version of the app in your browser. For example, you can either download Discord or Slack as a desktop app, or open them in your browser.

I'm not saying this comes for free; these apps are very heavy, and Flutter/React Native would probably produce more efficient apps.