What's the purpose of return end?

I know that this question may get closed down because it has been asked before but it never really answered the question. I'm not asking for what return does but i'm asking what's the purpose of putting an end after it? I've seen it used for debounces and such but i don't understand why people would use return end rather than just a normal debounces. So for what purpose does it serve?

It is basically to stop the code from going. It is usualy used to break a while Wait() or while true loop. Here is a expample of me using it.

function MusicPlay()
	if script.Parent:FindFirstChild("IntroSong") then return end
		local Number = math.random(1,3)
		print(Number)
		if Number == 1 then
			Music1()
		elseif Number == 2 then
			Music2()
		elseif Number == 3 then
			Music3()
	end
end

In some cases like that one it is required.