“Idle hands are the devil’s workshop”, as the saying goes. In other words, idleness brings about professional regression.
Each of us is granted a finite amount of time. If the decision is to squandered that time, the a non-renewable resource is lost: time. Meanwhile the competition has made an infinitesimal improvement that will be compounded daily. This adds up to a great advantage.
The choice is ours: small, daily improvements or basically nothing. Idleness is too expensive and must be eliminated.