Crowbars, Hatchet, and Flashlight are unique in that they can be carried as either tools or in a weapon slot. Crowbars and hatchets occupy the primary weapon slot, while flashlights take the sidearm slot.
The big difference between the Hatchet and the crowbar is, that the crowbar can be wielded simultaneously with a primary weapon and accessed by switching to it by pressing "F" (firemodes). This makes it possible to silently crush a hospitals glass or kill animals without having to drop the primary weapon to switch to it.
Currently, when using the Hatchet or Crowbar, the player must reload before it can be used to attack. This is a bug that should be fixed in the future. Despite needing to reload it initially, it will never run out of ammunition.