The idea behind them was to remove the work involved in learning and the effort required to teach.
In exercise you cannot get strong without effort, and there is no way to learn without effort.
The most effective way to teach someone and to learn is with a teacher, blackboard, and chalk. Everything else is second best (including the wonderful Kahn Academy).
And I still kind of think that was a solution in search of a problem. Are there any evidence that stuff like that helps learning?