A decentralized currency has many benefits over a centralized currency. The main benefit is control. No single entity is able to control the supply of a decentralized currency, making it difficult to manipulate the price. In a centralized monetary system, the central entity has all of the power, meaning they directly have control over the money in the hands of others. This is a liability to those engaging in such a monetary system because there is rarely a means of oversight. The central entity can take advantage of the currencies users without any consequence... (besides hyperinflation of course).