And as a heuristic for wealth, the ability to purchase an expensive ring is a reasonable metric. And that is what it is. As a heuristic for a good partner, it

And as a heuristic for wealth, the ability to purchase an expensive ring is a reasonable metric. And that is what it is. As a heuristic for a good partner, it is next to useless. On its own? Certainly. But wealth is an aspect to a good partner. All else being equal, the wealthy one is better.