I think what they mean is: 1. Don't do it for money because you will hate your life if there is no other meaning for you. 2. You are more likely to have blind

I think what they mean is: 1. Don't do it for money because you will hate your life if there is no other meaning for you. 2. You are more likely to have blind spots if you are chasing the money, and thus fail. 3. Chances of failure are high regardless, but if you like what you do you at least build skills that will lead your career in a happier direction. If it was just for money you are back at square one.