I agree that it's not a sufficiently precise term, but I think it's obtuse to suggest it's so ambiguous as to be deceptive or obstructive to discussion.

How's about: an act that is socially valuable has benefits, immediate or otherwise, realized by parties that aren't directly involved in the transaction.

Eg, a blackjack dealer's labor probably only matters to her players and her boss, but a cancer researcher impacts well beyond that. Both can be lucrative, but one is clearly more socially valuable.