You can't break it open, and it protects against thievery from others and yourself. In other words, once you put the money in, even if you want to take the money out soon, it won't open until you've accumulated a lot. So, however much you want to spend the money, even if you're broke, you have to save it until it's full. Anyway, it's saved. This is also known as a money bank that makes you persevere.