Yeah, 'green' trust is more valuable and merely being on default trust doesn't really mean much by itself, but a person in control of the account can use it to bolster his alts with feedback (and also leave negative (but abuse this way will likely get you removed from it if it's unjust)).
To most people being on default trust is in itself a stamp of being able to be trusted (even though it was not designed to be this way) in some people's eyes. I think it does walk a fine line to advertise a default trust account like this but there are non scam reasons to buy an account like this.
Edit: I think most people would consider giving your competition to be scamming
Obviously you do not need positive trust for signature campaigns...
