Sure, you could say the onus is on the people who use cryptocurrency for more than just crime or speculation to give proof about these uses, but for most detractors it'll never be enough, and for these users the benefits outweigh these negatives (or else they wouldn't be using crypto to begin with) so it's all an exercise in futility except maybe to convince any neutral bystanders one way or the other.
If I say cash and banks get used by the vast majority of organized crime I'd be factually correct, but I'd also be accused of whataboutism. In a world without crypto I'd be seriously hampered by an unfair economic system, so to me personally the pros outweigh the cons, but it'd be anecdotal evidence. Hope you see what I'm trying to get at.
Whether or not a technology's pros outweigh its cons is some appropriately weighted average across all the people that it affects. The person who gets hit by crypto-enabled ransomware likely feels differently from you.
I also think there is some moral weight to particular benefits. Dealing with unfair economic systems is definitely a "better" benefit (for some definition of good) than those people whose benefits are currency speculation or ransomware.
If I say cash and banks get used by the vast majority of organized crime I'd be factually correct, but I'd also be accused of whataboutism. In a world without crypto I'd be seriously hampered by an unfair economic system, so to me personally the pros outweigh the cons, but it'd be anecdotal evidence. Hope you see what I'm trying to get at.