This would be a perfect solution for the Playbook problem we’re having as well.
Since Playbook activity does not transfer in any way to a duplicate Deal (which is the only way for it to enter the Onboarding Pipeline without removing it from the Sales Pipeline), we have to manually visit the original Deal to see Playbook contents. The only option then is to update Properties … but if you update Properties via the Playbook, it overwrites instead of adding to any existing text.