Why can i set the networkowner to the local player?

Help and Feedback Code Review
#1

Hey guys. I have more of a question of a bit of code, as to why it works.

I have an NPC pathfinding system + ragdolling on death, which was lagging due to problems. I tried alot of different things such as setnetworkowner and a few other tacics. The way i solved this lagging was by adding SetNetworkowner to the local player.

module.SpawnNPC = function(pos, Class)
	local NPC = NPCFolder:FindFirstChild(Class):Clone()
	NPC:FindFirstChild("HumanoidRootPart").CFrame = CFrame.new(pos)
	NPC.Parent = workspace
	
	local decendants = NPC:GetDescendants()
	for i, v in decendants do
		if v:IsA("BasePart") then
			v:SetNetworkOwner(game.Players.LocalPlayer)
		end
	end
	
	return NPC
end
return module

Why did this solve my problem? I look through what setnetworkowner does, and it sets the owner to a single player. How can i set the networkowner to the localplayer? By the way, this does not reduce ping/incoming data, but fixed all my problems.

If i need to make myself more clear please comment.