Why can't I detect a change in a NumberValue if I change it in a localscript?

Hey Community!

I was working on a Roblox game, and I wanted to change a player's leaderstats from a local script. Here I have the script from the GUI text button:

local Button = script.Parent
local player = game.Players.LocalPlayer
local char = player.Character
local price = 50
function onClick()
    if player.trails.Rainbow.Value==0 then
        if player.leaderstats.Cash.Value>=price then
            local stat = player:FindFirstChild("leaderstats")
                if stat then
                    print("yep")
                    local cash = player.leaderstats.Cash.Value - 50
                    player.leaderstats.Cash.Value = cash
                    player.trails.Rainbow.Value = 1
                end
        else
            print("nah")
            script.Parent.Parent.Parent.Visible=false
            script.Parent.Parent.Parent.Parent.Parent.Error.Frame.Visible=true
        end
    end
end

Button.MouseButton1Click:connect(onClick)

When the leaderstats changes here, it shows up in the leaderboard, but the following script does not save it:

local DataStore = game:GetService("DataStoreService")
local ds = DataStore:GetDataStore("CashSaveSystem")
local ds2 = DataStore:GetDataStore("GemSaveSystem")
local ds3 = DataStore:GetDataStore("RainbowTrailSaveSystem")

game.Players.PlayerAdded:connect(function(player)
 local leader = Instance.new("Folder",player)
 leader.Name = "leaderstats"
 local trails = Instance.new("Folder",player)
 trails.Name = "trails"
 local Cash = Instance.new("IntValue",leader)
 Cash.Name = "Cash"
 local Gems = Instance.new("IntValue",leader)
 Gems.Name = "Gems"
 local Rainbow = Instance.new("IntValue",trails)
 Rainbow.Name = "Rainbow"
 Cash.Value = ds:GetAsync(player.UserId) or 0
 Gems.Value = ds2:GetAsync(player.UserId) or 0
 Rainbow.Value = ds3:GetAsync(player.UserId) or 0
 ds:SetAsync(player.UserId, Cash.Value)
 Cash.Changed:connect(function()
  ds:SetAsync(player.UserId, Cash.Value)
 end)
 Gems.Changed:connect(function()
  ds2:SetAsync(player.UserId, Gems.Value)
 end)
 Gems.Changed:connect(function()
  ds3:SetAsync(player.UserId, Rainbow.Value)
 end)
end)

When I edit the leaderstats from a normal script, it detects Cash.Changed, but when I edit it from the localscript, it doesn't. I'm wondering why this is happening, and if anyone knows how to fix this.

Thanks, Armacom03