The arrange track is a very powerful feature, not just for music production, but also and maybe even more for video post production.
In post your projects will typically be even bigger than an average song and so the arrange track will help getting an overview and moving and copying stuff around etc.
In a symphonic score there can be a really large number of tracks, so without the arrange track it can be a nightmare.
Only problem right now is, that it is not possible to somehow lock/exclude any of the tracks from the arrange changes and that is a big problem if you are doing both the dialog, foley, SFX etc and the music score.
You would then like to lock all these tracks and only move and copy the actual music score tracks. At the moment all your arrange track changes will change these tracks as well, destroying the video time dependent stuff.
The only workaround I know at the moment, is doing all the video time dependent stuff first, then export to a new video, importing that again and instead of importing the audio, just switching on the audio in the video player.
But that is very limiting to the creative process, that could had been so much better if you could do everything in the same session at the same time, not being locked to doing either one or another task.