"As deaths due to covid increased, the percentage of deaths due to car crashes has decreased"

I somehow think that doesn't mean we made any progress in car/traffic safety. And should not be used as an argument to dismiss/minimize the impact of traffic fatalities.

That is entirely consistent with a few possible (and I would say likely) explanations that include cryptocurrency being beneficial for crime. I'll cover one below.

If crime accounts for some small percentage of financial transactions (we'll say 1% to make it easy, even if that's very unlikely), and those transactions migrate to cryptocurrency first, then what you'll see is a very high percentage of crime in cryptocurrencies, that then drops as the much larger normal transaction flow shifts, even the total amount of crime transactions might be stable or even increasing (as we're talking about percentages of a whole, normal transaction traffic and would have to be shifting very slowly and crime increasing extremely fast for us to see anything else).

Keyword there is percentage.

That still doesn't make it a good thing.