Its like the forward assist.
And even if you were in the military, would you really want to force the last round forward and jam the gun for further use?
1 in a million that might work, but considering the lack of lethality (multiple 5.56mm shots needed) you would be better off whacking the assailant with the gun or pulling out the pistol.
I think of the forward assist like an appendix. An option that does nothing and adds cost.