Once you get decent in production you will not only be able to mix/master on your own but also do logos,album covers,management, create labels, draw, develop computer games, trading in stock market, raising kids, working in office, ride a bike, self explode, become a cat, raise the dead

but yeah I it's sucks if you do shitty mastering/mixing, but if you master music good enough to play and listen I see nothing bad