Breechplug
Crushing a pellet could actually cause you to crush or break a grains of powder if you broke enough of them you could change the pressure created in the barrel. Like changing from 2f to 3f.... It is possible you might get a bigger boom than you were thinking you might get. Not to mention how erractic the loads might perform.
In the case of APP sticks they suggest you crush them. Originally the APP pellets wre just like the Hodgdon pellets but Hodgdon filed a law suit and ended up causing the Clean Shot or Clear Shot to go bankrupt. So APP could not copy the pellet design again.