My best guess is that if you live in a 3rd world country you could possibly live comfortably just by a signature campaign, depending on which one it is though. For instance, Chipmixer which is mentioned on the thread has the capability of paying up to $300/week or $1500/month. This amount of money is way higher that Greece's minimum wage (approximately $850). Thus, if I ever entered Chipmixer, I wouldn't even have to work.
Personally, I'm satisfied on Roobet, which is paying $220/month for Sr.Members and is definitely a huge help on a monthly basis.
May this signature campaign continue and keep benefiting us.
Thank God we can survive on these campaigns from the comfort of our home without spending fuel and not to spend so much time on the road waiting for the traffic jam to be cleared.