In that case it is the strength of the imagined product.
It's also living dangerously: if the realized product comes close to what's imagined that's a very good play. If it doesn't it can be a ticket to the courtroom.
Also it's not an unusual situation for a first sale (particularly in consulting services) to be not at all reproducible and for there to be a long road to go from that to a playbook that works consistently.
