Limitations of fiat money include:

 - Devaluation: Fiat currency may lose value due to inflation, affecting citizens' purchasing power

 - Centralized control: The amount of money in circulation is decided by governments, which can lead to currency devaluation if there is excessive issuance

- Trust in the issuer: Its value depends on trust in the authorities that issue it, which can generate uncertainty about its future purchasing power

- Limited acceptance: A fiat currency must be widely accepted to maintain its value as a medium of exchange

- Dependence on economic policies: Fiat currency is subject to government policies that can affect its value.  

In short: it's shit money!