All value judgements are subjective.
All value assessment is made relative to need. If you don't need a thing, or any benefit that it can provide, then it has no value to you . So the value of any particular thing changes with every observer.
I assess value as a function of time invested and resources consumed with personal need as a multiplier. By this mechanism, a glass of water can carry more value than all the fine art in the world, to the thirsty man.
In the end, the only currency that anyone really has is their time.