What would be super interesting is to split data by the different category you mentioned yourself: currencies (coins for "just" payment, bitcoin competitors), marketplaces and platforms. How do their returns vary? Which category is performing the best? Etc.

I think that in the long term, most of the payment coins will disappear: there is no sense to have so many currencies. Even in the real world it's so annoying. But the potential for the last 2 categories is huge. Now, you're doing a month-based analysis, so I don't know if this is something you'll see in the short term. But still, interesting!