I don't convert my USD to Yen and call it an "investment." As stated below, some people do treat it as an investment to some extent. The other thing is, in my opinion more interesting, how you define crypto. They aren't really currencies even though people call them this way. They are a different kind of asset. Sometimes compared to gold, sometimes to stocks but it might be that they are just a new type and we just don't know how to value them. And by supporting them people support the technology behind.