This makes sense - I’ve never tried to solve pick depth by covering more of the pick with my fingers.
When I was learning to play early on I got ahold of the Stylus picks. I think they’re pretty similar in concept to this product, but in a sense much less forgiving. They play perfectly smoothly if you don’t exceed pick depth, but the second you do it’s going to catch on a sharp edge. I used them to try and train my hand to feel what maintaining minimal pick depth should feel like, and kept my grip roughly the same as I normally would.
I think the drawback of the stylus picks is that they de-incentivize you to find an angle of attack that actually works with a normal pick.
Just looking at this product, I’m guessing the drawback would be the tendency to press against it, causing a drift in posture when it’s not present. Might be interesting to practice alternating each of them in a routine when developing picking technique:
Picture for reference if anyone hasn’t seen them