You can style the widgets however you like. You don't have to use the default Material toolkit, the same way you can design Qt widgets in QML and don't have to use those default 1990s-style gray box widgets.
> remember alt-* to navigate menus?
I do, but most people reading this probably won't, or there will come a time shortly when most people won't remember. I think most people are used to everything being a web/Electron app. Users do not expect a standard design language (like Win32/Swing/Qt) for desktop apps anymore (and indeed a Win32-style desktop app will soon look as foreign as a webapp since even the Windows shell looks like a webapp now).
Flutter lets you create "webapps" (which is the new standard) but with native performance and ability to make syscalls (being native).
The only alternative tech stacks to this end are QML/QtQuick, JavaFX, an embedded WebView, or embedded Chromium (e.g. Electron or Chromium Emebedded Framework)--all of which having some sort of baggage. Flutter's baggage is you have to use Dart. The alternatives all also require that you use some sort of DSL (QML (Qt), FXML (JavaFX), JS (Electron)) so that's not a unique disadvantage. (It really isn't a disadvantage--imagine the hell if there weren't a DSL for the View layer and every language had to have bindings.)
GUI programming is downright suffering no matter which way you slice it. There are no interesting problems to solve, unless you're working on the GUI framework itself. Flutter makes this suffering slightly better. I don't see how it's not an absolute good.
> remember alt-* to navigate menus?
I do, but most people reading this probably won't, or there will come a time shortly when most people won't remember. I think most people are used to everything being a web/Electron app. Users do not expect a standard design language (like Win32/Swing/Qt) for desktop apps anymore (and indeed a Win32-style desktop app will soon look as foreign as a webapp since even the Windows shell looks like a webapp now).
Flutter lets you create "webapps" (which is the new standard) but with native performance and ability to make syscalls (being native).
The only alternative tech stacks to this end are QML/QtQuick, JavaFX, an embedded WebView, or embedded Chromium (e.g. Electron or Chromium Emebedded Framework)--all of which having some sort of baggage. Flutter's baggage is you have to use Dart. The alternatives all also require that you use some sort of DSL (QML (Qt), FXML (JavaFX), JS (Electron)) so that's not a unique disadvantage. (It really isn't a disadvantage--imagine the hell if there weren't a DSL for the View layer and every language had to have bindings.)
GUI programming is downright suffering no matter which way you slice it. There are no interesting problems to solve, unless you're working on the GUI framework itself. Flutter makes this suffering slightly better. I don't see how it's not an absolute good.