occasionally you may need to have a close look at some code (usually new to you) where you essentially need to see a lot at the same time. Then a printout can be invaluable for you to be able to look at the whole thing at one time.
Combined with a highlighter and a red and a grengreen pen it really helps getting the overview. The notes you put down on paper is then later added in some form to the code.
Note, with modern day color printers, you can get syntax colouring on paper too. That is really a great help and is highly recommended.
(I also print out specifications for reading - that is for putting notes in the margin.)