Manuals served another purpose in the 1980s: pirates rarely copied the manual with the game and so someone who bought the real game could learn how to play it while the pirates had a large collection of games that were no fun because without the manual they spent a lot of time trying different buttons just to see what worked - often they never did figure out the secret moves and so the game wasn't even winnable even though they could make progress and it seemed like they just needed to get better.