Well, in another subthread the author said he did in fact make a crashing PoC. I guess it depends on the customer's standards, but I would say in the vast majority of cases (especially for nuanced memory corruptions in which the ability to make something exploitable depends on your ability to demonstrate control of the heap) a crashing PoC is the bare minimum. In most VDPs, BBPs, or red team engagements you are required to provide some sort of proof to claim, otherwise you'll be laughed out of the room.

I'm curious which sector of infosec you're referring to in which vulnerability researchers are not required to provide proofs of concept? Maybe internal product VR where there is already an established trust?