Oddly enough, I found healing to be a type of skill to be developed before the hotkeys of healing came in. You had to be good at multitasking as you scramble through the menu to heal yourself. That said though, it was poorly balanced between players. Players with larger inventories were at a disadvantage due to the inability to properly store your items for a cleaner inventory. Tablet users were also able to open their inventory while moving around. Players with smaller devices cannot do this as the menu covers their entire screen. Meaning their character will stand still while the menu is active.

The hotkey was one way of fixing the unbalanced gameplay between different device users and players with cluttered inventories. Although it introduced a new type of unbalanced gameplay where:
-Streaking is a lot easier
-Basing is a food eating competition
-Low tiered weapons cannot kill heal spammers (It's practically impossible! Low damage per second guns cannot out damage the heal rate of the healers)