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. 