I thought so too, and bought two! One for my wife and one for me. You're right on one count: it does flush the inflator valve perfectly! But other than that, it's an exercise in frustration. Filling a BCD bladder (to rinse the inside) through the tiny orifice of the inflator valve takes FOREVER. And you have to stand there depressing the inflation button waiting for it to fill, so you can't just unscrew a dump valve, turn on the hose, walk away and let it flush.Using one of these to rinse the internals will help with salt tremendously, makes it easier to rinse bladders, and reduces service needs.
Amazon.com : Innovative BC Flush Hose with Inflator Adapter : Sports & Outdoors
Also, it doesn't flush the exhaust side of the valve any better than holding the valve open under a faucet.
Sad to say, I used mine only twice and then quit. Now, I hold the valve under a faucet and watch for squirting out of the bcd connection with the button depressed. I unscrew a butt dump and partially fill the wing bladder super fast with the faucet. I slosh around some "BCD Life" and let it sit. I rinse the exhalation valve by emptying the bcd, and then add a little air for storage.
My toy sits unused, because the limiting factor isn't the garden hose. It's the 1mm orifice of the inflator's Schrader (or other) valve. I guess the best of both worlds would be to use both techniques. Alas, I'm now usually at the bathtub faucet inside at night after a dive, and not outside with a hose after my frustrating trial of what initially looked to be a great invention.