 Since the introduction of Bitcoin in 2009, many new digital currencies have evolved. Digital currencies are a hot topic on global financial conferences, and no wonder. Since 2009, the value of Bitcoin has skyrocketed, making some people very rich very quickly. Moreover, Bitcoin operates without central banks and other institutions controlling and checking things. So why don't we just all switch to Bitcoin and cut out those nosy middlemen? The incredible increase in value of Bitcoin sounds great. Some also if you compare to the tiny interest rate on your savings account. However, the reality is a bit more complicated. To explain, let's look at the three main functions of money. First, and most importantly, money serves as a medium of exchange, facilitating transactions between different parties. Second, it is a store of value, allowing you to hold on to what you have for later. Third, money is a unit of account. It serves as a common measure of the value of goods and services being exchanged. While the value of Bitcoin has significantly gone up since the start of the coin, it wasn't a smooth ride, and Bitcoin's value still goes up and down on a daily basis. These quick and sudden changes in value disrupt the three main functions of money. With Bitcoin's value fluctuating strongly, it is unreliable for storage, since it could be worth a lot less tomorrow than today. Bitcoin would also not be easier to use as a unit of account, since its value can differ greatly every hour. And most importantly, transactions can become very difficult, because prices have to adjust to the new value of Bitcoin almost real-time. Also, many owners of the currency will postpone their purchases if Bitcoin is gaining in value, because they will be able to buy more things tomorrow for the same amount of Bitcoin. This means that consumers will postpone buying goods and services, grinding the economy to a halt. With other currencies, this is where the central bank comes in. The European Central Bank, for example, uses a number of instruments to keep the value of the euro stable. This ensures that your euros can keep serving all three functions of money, which in turn assures a strong economy for us all to prosper in. So while a currency like Bitcoin might seem attractive at first, without stability it cannot fully replace existing currencies just yet, and our central banks still hold a crucial role in our economy. Maybe in the future we'll see a central bank digital currency, but for now it might be wise to hold on to those euros.