Money is very important in the process of economic exchange. Before the coming of money, goods were mainly exchanged for a promise to return the favour in the future.  Promises were hard to keep when societies grew and economic activity improved.  There is a consistent risk of default and settlement risks were higher. 

The institutions which were issuing money were working through different methods to address the growing complexity of being able to maintain trust.

Money tries to maintain the value of the promises made, and therefore when it is used as a medium of exchange, the seller uses it as a means of payment.  It is easy to compare prices across things that are bought.  The expectation involved in the process of using money is that someone else will place a similar value in another transaction, thus money is a good store of value and users will be able to transfer purchasing power with time.

Money can be comfortable for use only when it has the same value in different places.  When it is not stable and the price keeps fluctuating then people who are transacting using that money will have to keep assessing it every time for value.  And, it will not be possible for users to determine if they can sell a particular good or service for a particular value.  This is one reason for why commodity as a money that has an intrinsic value simply did not work out and did not work well as a good support for exchange. Many times, commodity is perishable.

Therefore convenient money is important for any kind of economic activity. And, this means money should be able to deal with increased demand for the use of money.

Cryptocurrencies that are decentralized have high volatility and therefore is a problem when it comes to using it as a money.  Users regret having used crypto to pay for goods, when the price goes up after it is used in a transaction.   Merchants who have accepted crypto feel bad for having accepted it when the price goes down.  The lack of price stability is a major negative point for crypto to serve as a money.

Even with money backed by institutions, the trust has failed many times.  Money can fail and become inconvenient when there is a problem in political order and there is a great expansion in trade and economic activity.  The trust and stability changes at these times.  This means that the money we use now is not reliable forever. This is one reason for why there is a search for an alternative currency where the value can be preserved absolutely.