The Jewish sages believe that the financial well-being of a family largely depends on the wife (though the husband is the one who is supposed to be the main provider). There are lovely spiritual explanations to this, such that a peaceful and loving home draws the blessing of G-d, but I also think there are some very practical reasons to why a woman can make or break her home, financially included.
There is of course the basic fact that nothing influences emotional, spiritual and also financial success in life like a good marriage. Working together as a team, having the same vision, journeying together towards common goals, consulting each other and valuing each other's opinions is good for just about any endeavour, while the lack of this, when it feels like the two spouses are just pulling in two opposite directions, can be draining and exhausting.
Another thing, and this is something very, very important, some women are unaware of the deep intrinsic need of a husband to make his wife happy. It is of vital importance to a man to feel that his wife is content with what he can give her. And, opposing this, nothing discourages a man like a wife who always grumbles and is never content, and feels like she deserves to have all the goods of the world at once, disregarding the family's situation.
I guess I should say as a preamble (although I think it's obvious) that I believe there is nothing wrong in enjoying nice things, new clothes, a spacious house, eating out, going on trips, etc, etc - if it is affordable. Now, of course I'm not in a position to tell anyone what they can or can't afford, but I'll say what I believe to be the wise medium. If a family is out of debt, and the house is paid for, and they enjoy a good income, and are able to put something into a savings fund (for the children, for emergencies, etc) each month, why, then, they are lucky, and in the right position to treat themselves. But for many, many people this isn't the case, and don't get me wrong, but many times men see clearer than women about these things. I believe this is because women, generally speaking, have a more developed aesthetic sense, and therefore place more value in things like a big, handsomely fitted up house, new furniture, new appliances, nice clothes, jewelry, etc.
Of course there are also men who spend money on "men's stuff" such as gadgets, sports, etc, when circumstances call for thrift. But, as I am writing generally to women and for women, I will concentrate on our side of the coin.
Unfortunately, some women don't only fritter away the family money - and please note I am not making a distinction between "his" money and "her" money, because I believe that money earned by either spouse belongs to the whole family - but drive their husbands into reckless financial decisions, such as buying a bigger house, and taking on a bigger mortgage, than the family can afford. The consequences might be disastrous.
On the other hand, in hard times - lack of work, disability, unexpected expenses, etc - nothing cheers up a husband like a content wife who looks into the future with faith, and is ready to make the best of what the family does have. The crisis will likely pass, and when better times come, the husband will have more confidence to go on, because he will know from experience that, should something out of the ordinary happen again, he has a cheerful companion he can rely on. The worth of such a wife is, indeed, "far above pearls".