Thanks for the clarification, think that was greatly needed
However in what circumstances is the extra functionality of "On collision" a benefit or where is it intended to be used? At least in my experience I mostly used it with bullets hitting an enemy and then the bullet is destroyed. However you say that it needs to keep track of when the separation happens and touch again. Where as "Is overlapping" doesn't do this and just checks for an overlap, which is really what you need when a bullet hits an enemy for instant as the bullet most likely is destroyed.
Im a bit uncertain how to formulate the question , but can you give an example where "On collision" would outshine "Is overlapping" meaning where the extra functionality is obvious or what to say? or if anyone else can? I would appreciate it, because im happy with the clarification, but sadly I still don't see the reason to use "On collision" over "Is overlapping", so an example would help me?
A beam weapon that expands and hits an enemy, then keeps going and hits more enemies.
If you use Is Overlap, it will trigger many times on each enemy hit. If you add Trigger Once to it, it sometimes does not trigger on the subsequent enemy hits so the AoE is not reliable.
On Col works and trigger once for each instance and it will hit as many instance as it needs, but once only, very reliable.
The same applies for other AoE weapons, like an expanding nova or EMP circle, shockwaves, etc. On Col is 100% reliable.