I would suggest you don't understand the equivalence because it's not there. They aren't saying that creating something with polish is expecting to make money off it. They're saying when you start a new hobby or interest forget about trying to tailor your output to an audience that doesn't exist and focus on skill. Maybe you really want to produce something polished, but the reasoning for that should be for your own development and edification not because you want it to appeal to others. Prioritise what makes you happy and gives you enjoyment not what you think other people want.