On the board, the students can see where I am going to change the text or continue writing, as well as what I am commenting on and pointing out with my other hand. This is what makes the blackboard so effective.

If you want to replace the blackboard with GoodNotes, this would also have to be made possible. Technically, I think this would be possible. In presentation mode, the tip of the writing tool can be displayed (even before writing, in hover mode) and other parts of the text can be marked with a finger, which can be commented on and developed further.

This functionality would be a massive improvement in teaching.