Thanks for the nice explainer Kent. Just wondering from the product point of view, when you first sent the 5 messages, shouldn't the batching logic app show as Running, and wait until it receives the rest of the five messages? If the batch size was kept bigger, there would be a brief period of time when "Some" support users might feel messages disappearing :)
Not 100% sure but I believe it is just where you store your batch config. Do you store it in your workflow or is it stored externally (Integration Account) so you don't need to update logic app directly to make changes. I don't believe there is any performance benefit
