Reason #2 he will: Leading this staff means something
This ties back in to the beginning of the article. The Mariners have a really strong pitching staff, possibly the best in baseball. Especially when you look at the top-3 of a rotation.
To lead that staff, being viewed not just as the best of the group but as a true Ace, that truly means something. Especially if they all do as good as the oddsmakers think that they are going to do. If fans and voters are able to look at your team and see you as the Ace, the best, and the one leading the team (hopefully) to the playoffs, it's going to be hard to not vote for that pitcher as the Cy Young winner, aside from anyone else having a insanely spectacular or historical year.
Kirby has the personality and the "edge" that your leader needs. Sure, he doesn't look like a wily veteran or anything of that nature, but he's got that dawg in him and shows plenty of emotion on the mound. So often, we default to stats. Especially in baseball, when there is literally a stat for anything and everything.
However, there is that other part to it that matters as well. The inherent trust and belief that your guy is going to get it done, lead the way, and put the team on his back. Kirby is growing into that role, and this could be the year that he fully takes it on.