That puzzle is at least five years old. Seems a bit unfair to run a modern engine on it and complain about a slightly different evaluation.
Besides, Kg3 was suggested and disposed of years ago in the comments to the problem.
https://www.chess.com/tactics/172171/practice?autostart=1
Puzzle 172171, i chose g3, where g2 was the correct answer. I ran it under an engine and my selected move was -12.66 compared to -12.71 for chess.com's answer. Seems a bit trivial to me.
Anyone else disagree with some of the tactic answers sometimes?