The immediate reaction upon seeing poor financial decisions being made is to offer education. The assumption being, that if an actor had more information or know-how, they would make a different decision. People wouldn't spend too much if they knew how to budget, wouldn't carry a credit card debt if they knew how interest works.
It seems reasonable, but there is growing research that indicates the fix is not so simple. Here is a blog post by one of the leaders in the field, Lauren Willis, that lays out her main findings.
This is not squarely my field, so I won't categorically say that financial education is a waste of time, but it is certainly worth stopping for a moment to question the assumption that if we can just get people to take a course then they will adopt good financial decision making. Many researchers are now looking more toward prompting behaviors, like saving for an emergency, as a more effective at getting the "lesson" to stick.
Finally, it has been my experience that often what looks like irrational financial decision making to my US middle-class self is often perfectly rational given the world of the decision maker. I think it is important to see and understand and recognize that it is not just a stupid financial move.