I don't think it's particularly novel in 2019 to say that a successful app is built off of the feedback of its users. Any app, regardless of intentions or engineering prowess, is going to struggle if it doesn't have a sizeable user base providing feedback (and devs who listen to that feedback).
I can see an argument that enabling crime under oppressive regimes is moral. Or even enabling particular crimes that you feel shouldn't be crimes.
I have trouble seeing the legitimate use case for cryptocurrency in first world countries. If the main use case is crime, money laundering and speculation, it will either be squashed or remain niche.
Most people in the world don't live in a first world democracy. Today, many of these countries are stable and providing currency for their citizens. But ask a Venezuelan if they can see a reason why we might want an alternative to a state backed currency and I feel like the answer is self-evident.
Vitalik saw this use case and talked about how disheartened he was by the ICO boom because it was use cases like this that he believed in, so it isn't at all an afterthought.
Crypto people say this like it's an argument in their favour - whereas it actually means: even for its one and only genuine consumer use case, crypto is utterly trounced by conventional currency.