Composing movie music, there are often tempo changes in the same sequence.
When I work with a small orchestra, I use a click track sent to the headphones of each musicians, which can do the trick.
But recording an orchestra of 20 or 30 musicians or more, it becomes important to be directed by a conductor. The use of visual cues becomes imperative to properly direct the ensemble when there are tempo changes. This would be an addition that would allow using CbB in movie music sessions.
In the same vein, it would really solve the problem of offset, inset and startpoint videos when we work in the Microsoft Media Foundation mode.
I leave here examples to better understand the process.