If you really know the history of fiat, you will have an idea about how volatile they are and not to be trusted in terms of long term investment especially when the world is on the brink of another world war. That's why most investors are relying on Gold and Silver because for them these are the only real money and it won't decrease its price no matter what happen.

But sine we already have Bitcoin nowadays it is more preferable and convenient to have because you don't need to worry about transferring it no matter where you are as long as you have internet connection. Also the important thing is to easily bring it with you without even letting the others know you have them.