When I first learned of the Metabo setup I was puzzled because it doesn't seem to do much. It's not like it's X-lock.
It gelps eliminate the issue of users losing or misplacing the pin wrench used to remove the standard non-quick-change grinder nuts.
The grinder nuts don’t always have the same hole dimensions or diameter, and the average angle grinder user doesn’t own a set of pin wrenches.
If the grinder wrench falls out of tour pocjet, or gets placed on a bench full of random tools or other items, a lot of time can get wasted trying to find the wrench when you need to switch out accessories.
Multiple manufacturers were actually offering adjustable pin wrenches meant for angle grinder users who lost or were worried they might misplace the grinder nut wrench.
Jacobs at one point offered a couple ratcheting grinder nuts, that could be removed without tools, and my understanding, is that one of these designs used to be used by Metabo, maybe before the current system, although with modifications to prevent use on other manufacturers grinders.
Jacobs has long since stopped offering these.
The Fixtec grinder nut offered by Milwaukee, is a simpler more compact design than the Jacobs option.
I think from patents or trademarks I looked ip, it may have originated with a manufacturer in Taiwan?
The pop ip handle on the nut allows the use of an adjustable wrench in a pinch, and there are holes for a pin wrench, so it’s likely a better option.
Fein used to offer their own toolless flange nut, but it was proprietary, and the grinders didn’t have a threaded arbor, so it was eventually dropped.
It was also too complex.
