Because the Israeli army is often involved in very dangerous close-quarter urban combat, having wounded or incapacitated soldiers is bound to happen, and evacuation is often very problematic. To put it in perspective, it can already be difficult to navigate urban terrains when fully-loaded with weapons, ammo, water and other gears, so transporting a person on top of that may at least take out another soldier (if not two) from the fight, and that can be extremely dangerous if the tactical unit was small to start with.
The Injured Personnel Carrier (IPC) was designed to let one person carry another in a way that makes it possible to navigate small corridors, stairs, etc… while keeping both hands available for combat duty. The concept is extremely simple (therefore reliable?) and it basically turns the down solder into a backpack. When used in conjunction with a tactical vest, this could spread the weight over a much larger.
Now, non-combatant rescue personnel like firefighters are jumping on board, as this seems to be an effective way to carry people. Made by Agilite, the IPC costs about $80. Official video below: