Not to nit pick, but that is basically a variation of ROI. Return on investment, or very similar at least.
Value is not necessarily a formula but a metric. Exactly what you described as benefits. I think that is the practically the same since perception of value is based on the benefits. And it is indeed all subjective perception.
To make it even more interesting, perceived value could be totally manipulated up while actual received (quantified) value goes down. That's marketing. ;)
But yes, fun to theorize on this! :)
Pro tip: Be sure to put a bag over their heads from behind to avoid them filming it.