That is an answer to a different question—shminux did not ask why it’s relevant, but why it’s meaningful.
In other words, the question is not about the desirability of having simple aggregate measures of human experience, but about the possibility of their existence.
Why do you think it is meaningful to (simply) add human experience?
Do you mean why did I think this analysis was worth doing at all, or something else?
It’s relevant to some forms of utilitarian ethics.
That is an answer to a different question—shminux did not ask why it’s relevant, but why it’s meaningful.
In other words, the question is not about the desirability of having simple aggregate measures of human experience, but about the possibility of their existence.