Recorded music is great. I listen to recorded music all the time when I'm at the gym or at the office. I use it to set the mood. I use it to fill the silence. I use it to block out office noise. But here's the big question: could you go a week without listening to any recorded music at all? You'd be surprised how many people try to stop and find themselves feeling symptoms of withdrawal. That implies some form of psychological addiction, which in turn robs motivation.

The whole point of point 3 is to work for your rewards instead of getting them instantly at the push of a button. It's too easy to get addicted to the latter and with any kind of addiction comes a decrease in motivation.