Why use milk in scrambled eggs? I've seen many recipes for scrambled eggs with and without milk / cream / half and half

So what does the milk do?  The only difference I can see is color - without the milk the eggs are a brighter yellow.

What am I missing?
Well, it makes the eggs go further for one...

But it also produces softer, creamier results. You're moving toward something like a custard or quiche. If you like your eggs very stiff, this is probably a bad idea.