I haven't seen this comments, too busy at work, sorry.
Anyway, the idea is resembles 3check but instead the engine would register MATE THREATS. So the first player to have three direct mate threats (threat of mate in one move) would be the winner. There would be no mate or stalemate and no other way to win. Hence the name 3MT.
Although variants mostly differ from "real" chess, I find that some variants have a value as training for actual chess. For example, duck chess, has a value for defensive thinking, positions and lines of development. By learning to obstruct development, duck chess can visualize development and teach us to think in terms of obstructing the opponent's development.
Since mate threats are a constant strategic component in chess, I think it would be could to have a variant that focuses on this specific point, and that rewards the obtaining of mate threats and makes players accutely aware of them, hopefully even a few moves BEFORE they arise.
Yours
Spartakkus
we'll never feel that's enough