Yes, I think they are very useful.
You could have different arrangements that use the same loaded instruments which could also be saved as a rack (meaning saving the whole vst instruments (F11) rack and even saving the state of the mixer would be awesome rather than having to recreate from scratch.
Imagine: you have your orchestra set up as you like it and just add another arrangement (like you are going to make another movement/take/variation) nothing to reload!!!
Like a workspace only more powerful…
one can only ask…