And thirdly, few would have known that the ballista has infinite ammunition and a battle tactic involving a single ballista :) if the organizers hadn't created such battles. I mean, maybe no one would have even figured it out if all the upgrade stations and boxes were placed on maps without any guards.

Why go to extremes... to showcase a trick or a bug with the ballista (I honestly don't know what to call it correctly), you could simply place 50, or even 100 golems... those who know the trick/bug with the ballista would have grabbed the prize on the first day, and those who don't know wouldn't (and the fact that the battle takes a lot of time would automatically be eliminated). And there would be no need to waste time on such a battle, and there would be no need for any kind of automation.
Also, what's the point of a battle with 1 fairy against 1000 skeletons? You could simply place 50-100 skeletons, the main thing is to grasp the meaning of these battles, but not to sit in front of the computer, engaging in nonsense for several hours, struggling with the battle.