Haha!
Yeah, I guess that begs clarification.
Less solely about money and more Nami's no-nonsense sense for what would be beneficial and prudent at all times based on a complex set of theories, rules or experience which she may not actually reveal but are all steadily in place.
I've had discussions where I've believed something to be the right choice no matter what angle you look at it from and Oda calmly explains his way of looking at the issue and it might not always be a sparkly-eye-inducing game-changer but it always makes you think, woah, I had not considered that.