It is worth trying rather than leaving the signature space empty and waste the possible opportunity these bounty campaigns offer us. As you can read on the previous reply, some signature campaigns offer a good reward, and won't you believe that somewhere in 2018 from the other forum, most of the participants on one bounty campaign earns more than $20k in just a month or two post tasks? So never underestimate the opportunity this signature campaign offers. Many maybe end up as scam but who knows when will be the next gem for signature campaign participants.