Here's the thing: there isn't a point where a gymnast crosses a threshold and is suddenly doing skills that put undue strain on the body. Right from the start, we pound our bodies in ways they weren't designed to be pounded, hold our weight in ways we aren't designed to, and endure workouts our bodies weren't designed to endure.
I see no problem with braces, taping, and anything else that can potentially prevent overuse injury, EVEN IF THERE IS NO PAIN YET. As every physical therapist knows, prevention is easier than rehabilitation.
The sport is evolving. The equipment is evolving. Our bodies can't keep up on their own; if we have the tools to allow our bodies to handle the forces without getting injured, why not use them?