What do they do and what's the point of them?

They can be used to block actions from executing unless a certain condition is met. For each action you can select a condition and whether it should be "set" or "unset" (you can see this as true/false, or checked/unchecked). If the condition is not met, the action is skipped.

The most simple use-case is showing/hiding widgets with an animation. Once a widget is already visible you don't want the animation to play again even if you accidentally click the Show button again. A condition flag is a simple way to block the animation from playing a second time.

They are used a lot in the ATVO Theme.

More here: https://atvo.appgineering.com/Forum/Thread/307