It's good, but it's work. I have a friend, really good swift/iPhone dev who charge 350 to 500€ an hour (so 200-350 after taxes). If after taxes and expenses (loan repayment) he can earn 2-3.5k for less than 10h of work per year that can be a good investment. But that's not taking into account the principal he invested, the fact that the job would bore him, the fact that he can't improve his skills.

It might be an okay investment for me (I'm a salary man, can't be bothered with freelance work), but for him I'd bet it's a money loosing proposition

[edit] the 500€/hour is an outlier, he wanted out of a project and kept increasing his rates, which were accepted up to that point.