This setup demonstrates a setup of prop-based health kits which could be parented to a moving object, or positioned somewhere like a cabinet without being affected by physics. It uses the logic_playerproxy entity to determine the player's current health value before providing aid, to ensure players do not use health kits when they are already at full health.
This is just one example of what the entity is capable of; a similar setup could be created with ammunition boxes for specific weapons, for example.
Also, Rabidmonkey posting a map? Your workload on BM must be lightening up!
Specifically, I had a level where players were on a moving tracktrain (boat) while fighting a helicopter. I needed a way to give the players health, but health chargers cannot be part of movement hierarchies. Normal physics-based health kits wouldn't work, either, because of the potential for collision errors, and health kits falling into the water where players couldn't access them. So, this was the next best solution - it provides the effects (adding health, sound, props disappearing) of using a health kit that players are used to, without any hard code. In most situations a regular health kit should suffice, and I would suggest using them over this method, because players are conditioned to being able to do specific things with certain items (like carrying health kits as physics props)
Plus being able to relay inputs/outputs to and from players, and using specific player actions or values (like ammo or health) has a number of possibilities for single-player games, like enemies that only spawn/attack when the player is above a certain health threshold, or events that occur in certain areas when the player uses their flashlight.