No, it doesn't give less cheaters. Have you ever looked how it worked out on hypixel?
First of all, almost no-one plays it (0.25% of the server). Secondly, it doesn't give less cheaters, but it increases the amount of first time cheaters (stated by the owner of Hypixel). Thats why they almost want to remove it. Because there is a ranked system, more people want to be ranked high. Some people then go to cheating. And if you (a legit player), plays against all those hackers over and over again, the chance of you (maybe not specificaly you but a lot of players) will also turn to cheats, because they dont see anyone being banned, and so they think they can keep cheating.
About the tryhards, no, they will also still be playing normal skywars. It doesn't mean that when its added that they stop playing 'normal' skywars.