Yeah, I don't like flash nosebands

! I think because people do them up so tight (originally so that the flash strap doesn't pull the cavason down) but now more than ever because they want the jaw immobilised

What people don't realise is that when the horse is going correctly, the horse opens the lower jaw away from the top (slightly) and the lower jaw drops forward. If the horse isn't able to do this correctly the brachiocephalic muscles can't work correctly and the snappy action of the forelegs creep in.
I think the drop noseband is more likely to allow for that correct relaxation of the jaw while allowing it to drop forward also. But none of mine need anything like that, indeed I rarely have a noseband on any of my bridles.