I remember when it was just exactly the opposite and the struggle was to get away from slow-fire shooting, adding power, speed, and much-reduced time-frames into the competition mix.
For what it is worth, I do continue to shoot pure, non-timed, slow-fire bullseye shooting at both the beginning and conclusion of each range session. The reason is that for me, it forces me to go by the basics of sight-picture and trigger-control better than anything else I've tried. I find that if I work solely on the fast and furious "practical" style shooting, I inevitably wind up "slapping" or "jerking" the trigger in order to get shots off quicker with sufficient (coarse) accuracy for the more-generously scored targets associated with this type shooting. Only by getting back on the boring and merciless bullseye work am I able to maintain being able to shoot a bit more precisely as well.
Speaking only for myself, I prefer to do both and see a purpose for both disciplines.
I shoot from a rest when seeking to eliminate as much human error as possible from the resulting group. In other words, when trying to determine a particular firearm’s built-in potential accuracy, a rest serves better than free-hand, at least for me. It is also part of the protocol when I’m trying to adjust sights, be they adjustable and especially if fixed.
We must not confuse what might be achieved from a rest in slow-fire to the results from shooting without a rest or in “practical” style exercises, but to simply assume or even proclaim that precision-shooting disciplines as worthless is a flawed view in my experience.