If you have a hero or legendary rank, post high quality content, and post very often you might be able to get like 20$ a week. You'll never be able to make a living or anything like that, but it doesn't hurt to get a few bucks to post (and it is especially nice if you already post and the Sig campaign is just a bonus payment for something you do regardless).
I am not sure in which campaigns you are participating where hero/legendary are getting 20$ at max, ( ~0.0156
BTC) per week, but that is not the case for most campaigns.
I often see Hero's/Legendaries getting around ~0.04/0.05
BTC weekly, for around 30 posts.
Bitdice, Duckdice, Bitsler, Coinroll, to just name a few campaigns.