I see you look at the thing with a stats mindset and this is why that mindset is completely irrelevant when your job is to take out who is in front of you in a 7 game series. The playoffs are matchups and thus don't have huge number samples, both in opportunities and population, to do stat analysis. You must perform the eye test.
If your center is someone who plays a puck possession game goes against an offensively minded center, your 2-way center might have less numbers than the offensive one but in a straight up matchup, not only can the 2-way center contain the offense of said center, it can neutralize the passing game both from the center to the wings AND the passing game from the wings to the centers.
The game is not who has the best stats, it's about who wins the game. It's not about scoring goals but who scored the most. That means you can win 6-5, you can win 1-0.
This is why centers with huge regular season numbers and awards like Joe Thornton and Auston Matthews can dominate the regular season but have no Cups or even long playoff runs to show for it. Thornton has only one Finals, a loss, while Matthews has never had a Final appearance so far.
One thing to always consider about the playoffs; the further you go, the more likely you will need to have better matchups because the teams that keep winning are the ones who have succeeded in executing the matchup game.
Lastly, the gambling argument is silly. Every experienced handicapper knows that hockey of all pro sports is by far the most difficult to handicap in terms of goals.