The problem with fiat currencies is that they don't have a supply limit. You can see that the central banks have printed trillions of dollars already. This will flood the markets with new money. People and corporations will get free money. However, the problem is the more something is available the less valuable it is. So, if the central banks continue to abuse their money printers, soon we'll all become millionaires. We'll have 10's of millions of dollars, but the problem will be we won't be able to buy much with a million dollars. They will be enough only for a single grocery shopping.

On the other side is Bitcoin. It has a strictly limited supply which no body can inflate. This way Bitcoin is scarce, and you know scarce things are more valuable than abundant ones.

So, with the current situation, we need to turn our fiat currencies to Bitcoin. The rest of the alt coins are too small with much worse security and are often centrally controlled. In one word they're too risky! So keep your money in Bitcoin!