To give an example comparing a text field in a native OR webview-based macOS app with a hypothetical Godot-based one, the Godot version would need to reimplement (or likely just omit):
- Copy/paste
- Emacs/readline keybindings (Ctrl-A, Ctrl-E, etc.)
- User's preferred text size and font as selected in System Preferences
- Spellcheck
- Nice features for non-latin text (e.g. built in pinyin keyboard)
- Crisp text rendering
- Dictation support
- Screen reader support
- Autofill
- Automatically updated with OS updates (e.g. HiDPI, all Java UIs had looked almost-native but were now stuck looking pixelated)
- And hundreds more features I'm forgetting...
This is all possible to do in Godot (e.g. the Godot Editor does a lot of these) but with a lot of work required. It's completely built in to any native or web-based text field and doesn't need any additional work.