Signature campaigns with the payment in Bitcoin are very rare and it is very difficult to participate in it. A lot of people want to participate in such bounty campaigns.
Their signature campaign is not quite as standard as many are used to. There take only on 5 participants (starting from full member). And number of posts in week quite large-25 (and was at all 30) But payment in BTC is good.
It is not wonder that the conditions of signature campaign are so strict - 25 posts a week. Now it is very difficult to find a bounty campaign with payment in Bitcoin.