In a sense, but all that a Z move does is magnify what’s there for a single burst of power, regardless of whether the Pokemon would naturally be able to sustain such a thing. It wouldn’t surprise me if there were side effects of some sort that will be brought up in later games, that tends to happen with Pokemon.
The Key Stone is required to achieve Mega Evolution, and from all indications is naturally occurring but inert without input from a human.
({wait, i thought the key stones were naturally part of the planet? at least thats what the show said, i think, and...
So….almost exactly like any evolution stone?