I bare shaft tune only when a bow is a problem. Bare shaft tuning IMO is just another tuning method. You could easily forget it and paper tune to start the process and walk-back tune to finish. I really prefer walk back for precise settings.
Bare shaft tuning WILL turn up any vane contact problems if you can't get good tears in paperor are having a problem w/ walk back tuning.
That is essentially when I go to bare shaft tuning.