That's it exactly. Because of the constant money printing, the constant inflation, the constant devaluation, it's not enough to just "have" fiat. You have to spend a great deal of time (or a good chunk of fiat to pay someone else to do it for you) balancing investments, assessing risks, opening and closing accounts and portfolios, moving fiat around, etc., always trying to beat inflation. And even then, sometimes you are lucky just to break even.
And this in most cases stimulates economy in wrong direction - there is demand on goods where it should not be. So money does not work efficient and people do not work efficient for long term economy grow. There is the mass of hidden flaws in this system despite all those visible at first look.