Popularity of Electron proves that they are not easier. Even Microsoft wrote VS Code in it.
I don't care much about Google but they did pretty good job with Flutter:
1. No special designer needed, you do everything in code. That means everyone can use their preferred editor.
2. Hot reload - you change something and it changes in the running app.
3. Headless testing - No need to own iOS/Android device to test iOS/Android UI.
4. Nice tooling - autocompletion, formatting, etc. Everything done via command line, with optional support for IDE.
5. Extensible - very easy to write your own widgets. There is nothing special about provided components.
6. Platform agnostic - "native look" of Qt/GTK is a lie, they still look off. To me it just triggers uncanny valley vibe. Not to mention that they implement native look from 5 years ago or more. And completely useless on mobiles. Flutter looks the same on every platform unless specified otherwise. Way less platform specific bugs.