Never used the contraption, never even seen it, but i have helped before. It always reminds me of those commercials, "its shake and bake, and I helped". Anyway, AI isn't better than the real thing. The natural act "primes" things so to speak and you miss out on a lot with AI, just a fact.
and if you want a certain bloodline there are cases when you "need" to help for the safety of your dogs. breeding in the wild isn't always pretty, there are more than a few animals injured during mating rituals, its just a fact of life. When someone has thousands of dollars invested in the dam and the sire, most people do it as precautionary measures so one or the other don't get hurt.
Like I said i've never seen the contraption before, but helping during mating is nothing new and its done by lots of people that have nothing to do with puppy mills.