I agree because your hobby might have less demand or you have no reputation which people prefer to use service from reputable company.
if your hobby somehow happens to be trading stocks or crypto example, then you can easily earn money, gain some edge because you're so committed since it's your hobby anyway and achieve financial freedom.
That's not hobby, but you're intentionally learn that in order to make money, it will be considered as skill instead of hobby.
Hobby is something that you have no intention to make money, name it playing football, basketball, painting, customize something. Let's say playing football, you doing it was pure for happiness, but if you're good at it, you might be hired to become a coach or you're become professional player.