Because I reload and with the flick of the bolt the brass is in my hand then my pocket. Once there I can then go field dress my deer and not have to crawl around and look for the brass in the grass and snow.
My brother has a pump action Remington 760 and he catches the brass from it also.
Semis are a military weapon because the object really is to maim which ties up more people to care for them so less persons to fight.
Al