Thanks for the answer @Anonsteve!
The Creative Commons BY-NC (non-commercial) license defines non-commercial as “Not primarily intended for or directed towards commercial advantage or monetary compensation”. The interesting part here is the “primary intention”. Could I claim that the primary intention was to share knowledge or entertain or something, and earning some tokens was just a fortunate side effect?
Possibly. I'm by no means an expert but if your monetary compensation was incidental and not based on an agreement of any kind, I think you'd probably be on a strong footing in court.
Also the earnings will probably be so small that any company would ever sue over that.
Still I think I will go by your first recommendation and try to always use freely licensed content and I recommend everyone else to do the same, unless Creative Commons changes their terms and explicitly mention sites where you can earn tokens with real value.