These are ways we can easily use money wherever we have such necessity. But to save them we have to do more than just keeping them in fiat. Because fiat money is not a reliable asset, it tends to inflation or deflation, it also inclined to be destroyed or blocked or lost. And you cannot be sure, that you will have access to it, when you need it. That is why you should concider other ways precisely for saving, and it can be investing included.