First apologies if you took offense at my joke.
You stated you were surprised that no one had mentioned that particular device, and your right, perhaps it is because it is not considered an essential piece of equipment for filling a radiator?
I own and run a garage business, and have never needed anything other than commonsense to fill a cooling system, and trust me, if the product was even remotely advantageous to the garage trade, I would have a rep crawling up my arse every other day trying to sell it to me, along with anti scuff door protectors and dashboard polish.
Regards
Dave