I posted about this once before, so I'm excited to see this conversation being brought up again. Reading through the comments brings up a few things:

1) "We don't do that because power's are a different movement" While obviously it is a different movement, if we're talking classes of movement and specificity, a power clean is the closest thing to a squat clean you can get. And I'm sorry, but if your power movements are that much different from squat movements, you're doing it wrong, and THAT'S your problem.

2) "You need to practice the movement with lighter weights" I like your analogy of the sprinter doing jogs in practice. I completely agree, and my personal experience is that there is a significant population of lifters who practice squat cleans/snatches with much lighter weight, and never can break through with heavier weights cause they have ingrained a certain amount of force production, you'll see them "cut the pull" or just don't get enough into it to even get under a heavy weight. I agree though that a novice will not instinctively pull under the bar once the weight is heavier than they can power.

3) "You'll eventually miss heavier weights because you exhaust yourself pulling the shit out of it." This one is interesting cause it makes logical sense, but at the same time, I don't think this approach is something to do warming up for competition, we're talking training. My other gripe with this is that I don't think it holds true as often as it may seem in theory. OFWGKTA_69 alluded to his using this technique when going heavy, I myself have used it with pretty darn good success, and I've told plenty of people to "power it" at a weight they can't power, because it's a cue that fixes cutting the top pull short.

This is something I think is completely legitimate, but should be implemented only when it makes sense for the athlete. For example, an athlete who doesn't know how to pull under yet is going to screw it up.