Weapon durability is kind of essential in the formula for encouraging people to hunt a variety of different monsters and explore different locations and using a variety of different weapons. Otherwise the game becomes basically nothing but avoiding everything bigger than a Bokoblin and killing everything with an unbreakable savage Lynel Crusher and Savage Lynel Bow. Otherwise, remove everything cool from the game because it’s overpowered and invincible.
Well is it essentially a dynamic leveling system.
If you go off and fight weaker enemies for a while, your weapons and damage output will scale to their level.
It allows players to fluidly go anywhere and scale quickly to that area's power level.