The hole at the rear of the bottom of the grip serves no particular purpose, other than to let crud, mud, and water fall out.
It will not do much, to help you to remove the magazine.
It is neither good nor bad. It just is.
Some people buy a plug for that hole, and some of the available plugs include a tool that aids disassembly of the gun.
Other people will tell you that you shouldn't plug that hole with anything, and that you don't really need a disassembly tool.
It's your gun, so it's your choice.