If you don't put it in appropriate size bags, you will know soon enough if a couple pieces slip through the bottom media basket and destroy your impeller or motor soon enough. Of course by that time (if you ignore it) you may have to order another impeller and or motor much earlier than if you had properly bagged the media. Another "option" is to put one of the reticulated high flow sponges at the bottom of the bottom basket that the matrix can't get by, and put the matrix unbagged on top of that.
The choice is, of course yours to make. Pay with "time" now or a lot of money later.....
YMMV