Signature campaigns isn't just about advertising anymore.It has become a part of the bitcoin culture.One of the primary reasons which allowed normal internet users to make some bitcoins without investing anything but knowledge.You can be very sure that your product will be famous among the largest community of crypto-lovers in just a matter of few hours through signature campaigns.
That is right point and with your point famous I will say that with signature campaign if any person do not get direct members with the link in the signature then it does not mean that signature campaign not working as the main purpose of signature campaign is to make famous your product in the community. For a particular purpose/service/product people will know about your name and whenever they will need that purpose/service/product then they will come to your site. That is the benefit of signature campaign.