Because some people consider it a safety hazard to have to take the rifle off safe to remove a round from the chamber.
^^^^^^^^^^^^^^^^
THIS
Ive had both and just prefer to open the bolt on a live round with the rifle on safe.
And yes Ive replaced a few triggers and the bolt lock feature goes away
Calling predators and getting in and out of vehicles and box blinds necessitates a lot of chamber loading/unloading...just makes me feel better....