Besides what was already said, there are three major good reasons to invest in cryptocurrencies. First, because you want to hedge your net-worth against the fall of the Dollar imperium, which is assumed by many people to inevitably happen at some time. Second, because you support the social vision behind cryptocurrencies – that of a free and hard money for the whole world. Third, because you understand and like the technology.
However, there are also very bad reasons to invest in cryptocurrencies. Many people fall victim to the hype surrounding every cryptocurrency-bubble. There is always somebody captured by FOMO (fear of missing out), buying massively in at the peak of a bubble, just in hope to make quick money, while not understanding cryptocurrencies at all. That’s a bad reason. Don’t do this. Learn before you invest.