I am having issue with datastore service. Ideas?

:UpdateAsync() takes a function, not the value to update the data store with. Note that, if the passted function does not return or it returns nil, the update is cancelled. The function cannot yield either, so do not call wait() ,event:Wait(), etc

PointsStore:UpdateAsync(player.UserId .. "-Points", function(prev) -- prev is the previousvalue
	return player.leaderstats.Points.Value
end)

Also, why are you using coroutines like this? You should just move your while loop to the bottom of your script. Additionally, Instance.new's second argument is deprecated. Set all the properties of an object first, and then parent.

local Players = game:GetService("Players") -- Stay consistent! Why call :GetService() on DataStoreService and not Players? Why not have a variable for Players as well?
local DataStoreService = game:GetService("DataStoreService")
local PointsStore = DataStoreService:GetDataStore("PointsStore")

Players.PlayerAdded:Connect(function(player)
	local success, points = pcall(PointsStore.GetAsync, PointsStore, player.UserId .. "-Points") -- wrap web requests (data stores, http requests, etc) in pcalls
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player

	local Points = Instance.new("IntValue")
	Points.Name = "Points"
	Points.Value = success and points or 0
	Points.Parent = leaderstats
end)

Players.PlayerRemoving:Connect(function(player)
	PointsStore:UpdateAsync(player.UserId .. "-Points", function(prev)
		return player.leaderstats.Points.Value
	end)
end)

game:BindToClose(function()
	--[[
		When a server is shutting down,
		it focuses only on shutting down,
		so your PlayerRemoving event listener will not be called. 
		You should save on BindToClose as well.
	--]]

	local playersInGame = Players:GetPlayers()
	
	for _, player in ipairs(playersInGame) do
		spawn(function()
			PointsStore:UpdateAsync(player.UserId .. "-Points", function(prev)
				return player.leaderstats.Points.Value
			end)
		end)
	end
end)