I tried adding potions instantly but that just wastes a lot of them since you generally collect potions only at the start. For instance why would you automatically add a health potion when a player is at full health? Or a breathing potion when player is at full air bar? I decided to leave the choice of using it to the player. It's just two keypresses, after all, one to select the inventory slot and then the E key.
Thank you for rating the game.