manual
What it provides is not having to do manual filament switching, its the entire purpose of it.
“I dont see cruise control providing a lot that manually pushing the accelerator pedal doesn’t.”
Another thing to also try is gently chamfering the inside of the inlet part of ptfe-tubes. Sometimes I have seen filament facing slight resistance when hitting the edge of the ptfe tube during load and causing the printer to warn about AMS feed resistance.
I’d love to see a ‘real’ filament track switch, similar to the manual version posted by @GeoffS but driven by the printer. The current BBL FTS is of limited use because it can’t really change AMS assigment as freely as I usually need it. I’ve used the FTS with 2 AMS on the X2D and for this scenario it could make sense if it would work without issues, which wasn’t the case (might be resolved by now by firmware updates…)
Now I have 4 AMS2 (plus 2 HT) in my setup and have to re-route them quite frequently to match the filaments to current print projects. An automated ‘manual switch’ would offer the possibility to even change AMS assignment mid-print. Or BBL makes it possible to use more than 1 FTS, that might work too 
As you dont have to re-route anything if you have a FTS and enough 4in1s, I suppose you mean that you re-route your AMS units to decrease print time.
If you have more than 2 AMS, you still have to put them together in one of two groups. If you want to print filament from two AMS in the same group, one with the left and one with the right nozzle, then at each filament change, the printer has to retract the filament, switch the FTS path and load the new filament in the other nozzle. When each AMS is switched individually to one nozzle, then both filaments can stay loaded all the time.