The problem is that if you have N scenes, then you need N Videos to create previously with CTA
Then you need another external tool to mix together the N videos
Another problem is that the borders between scenes are very dificult to adjust with separate videos
The same happen with the audio that it is more dificult to adjust wit several videos
So I think this approach is only suitable if there was not another way.
And there is that other way just including the N scenes in one unic CTA project.
See: CTA2: Multi Scene Tutorial
https://youtu.be/_3VNURoNghU