If this is just planned to be removed eventually, see full linked comment above, just that would be a beneficial bit of guidance.

From what I can tell, while there are no more uses of MaterialButton in the framework (after removing the deprecated buttons - Flat, Raised, and Outline), there are still a lot of customers that use it - a lot.

A MaterialButton just basically creates a RawMaterialButton, but the big difference is the former supports inherited themes while the later does not. I think the mention of the old button should be removed from the docs, as well as the "this is obsolete" distinction to avoid confusion.

Since this is still a heavily used widget, I think the docs should just focus on the use cases with theming in contrast to the Raw one - rather than how this widget used to be used. It affords folks a totally customizable - and theme-able - button, in contrast to the already configured Text, Elevated and Outlined buttons.

Agreed, after removing the deprecated buttons, MaterialButton is no longer actively used or very useful in the framework. However, I'm sure there are still many customer projects that use it for various purposes, so there is always that to consider too.

The MaterialButton is imo not so useful as a raw button building block. The RawMaterialbutton fills that role better and is used for it in the SDK too. Although only by FloatingActionButton and ToggleButtons, so not so much. Still it is a useful building block for custom buttons.

As a reminder, MaterialButton is also referenced in a large number of getters in its ButtonThemeData, where you pass several different getters a MaterialButton and it contains things e.g. like this:

  Color getSplashColor(MaterialButton button) {
    if (button.splashColor != null)
      return button.splashColor!;

    if (_splashColor != null && (button is RaisedButton || button is OutlineButton))
      return _splashColor!;

    if (_splashColor != null && button is FlatButton) {
      switch (getTextTheme(button)) {
        case ButtonTextTheme.normal:
        case ButtonTextTheme.accent:
          return _splashColor!;
        case ButtonTextTheme.primary:
          break;
      }
    }

    return getTextColor(button).withOpacity(0.12);
  }

Where MaterialButton and in above example case all the deprecated buttons are referenced too. So to remove MaterialButton', FlatButton,RaisedButton, OutlineButtoncompletely, theButtonThemeData` class has to be modified quite a bit, or also removed.

I think it's deprecation and removal is on the roadmap now too, mentioned at least in this comment #53378 (comment), but I did not see an issue issue on it yet. If it exists, it might be good to add to the ThemeData clean up collection #91772 and/or at least here #98691.

In any case complete removal of the classes for the deprecated buttons cannot happen unless it is also in sync with needed changes to ButtonThemeData, if it needs to remain a bit longer, or its complete removal.

This is going to be deprecated, will sync with @TahaTesser's work first

Had a sync with @TahaTesser, I am un-assigning myself from this currently to go focus on refactoring FAB (#99086) to remove dependencies there in order to make removing this class in the future possible.