I knew the guy who invented these things. He frequented an open mic jam I used to attend in Doylestown, PA. He approached me, talked it up, and gave me one to evaluate before it went to market. I thought it would be more marketable as an exerciser, something that would provide real resistance so you could strengthen those heel down muscles.
But it has about as much resistance as your pedal, and I really didn't see the point. I could do the same thing with my foot on the floor. I relayed my thoughts to him. Then, a few years later, I saw it advertised in Modern Drummer. It's essentially the same prototype as I tested, with the addition of a holder to attach a beater rod. I thought if he could design it with adjustable resistance, he might have something.
IMO, to properly practice the heel down technique, you really need a rebounding surface like a drumhead or rubber pad so you can let the beater rebound fully after every hit. This just doesn't simulate that at all.