If a knife comes with a cutout in the frame such as an easy open knife, I can see pinching the blade open as that's what the cutout is for but I don't get why someone would want to have a knife that has a blade that is pinchable - that's what the nail nick is for - to open the blade. In other words, I don't see the appeal of having a knife with a pinchable blade other than an easy open knife.
Anyway, I do see the need for a blade opener for people who as David said have an infirmity of one type or another.