- Athletes practice their skills; practice, repeat, fast, slow, different conditions, etc
- Scrum gives people an opportunity to practice the elements of the SDLC
- The timebox is the anchor of this learning/improvement aspect
- Sprints bring a regular rhythm or cadence that provides a structured and safe backdrop in which to experiment and learn
While Kanban proponents advocate evolutionary change it might lack the rhythm that helps people learn effectively. On the other hand Kanban enthusiasts talk about the need for cadence to help the team work effectively.
Maybe Kanban laid over Scrum would be a better implementation than Kanban laid over Prince2.
Having said that, maybe Kanban is a better model for getting work done once you are ready to move off Scrum's "training wheels."