I don't know how you want to increase the player's speed, for example it happens when you touch a brick or a key bind. Since you're using a server script, you're trying to access the LocalPlayer, but that's only available through local scripts, not server. Either you can put your original code in a local script, or you can do this:
1 | game.Players.PlayerAdded:Connect( function (plr) |
3 | local char = plr.Character or plr.CharacterAdded:Wait() |
4 | local hum = char.Humanoid |
5 | hum.WalkSpeed = game.ReplicatedStorage.Points.Value + 3 |
This code goes in a normal script. Put this script in ServerScriptService. I also noticed you're trying to set the WalkSpeed from the character. It's the character's humanoid that you do this to, not the actual character.