I think you're exactly right. Cryptocurrency is built for a dystopian future where the people have access to stable, unmonitored internet (in other words, a contradictory situation that will almost certainly never exist). If the dystopian country retains the technical capacity for widespread internet, the dystopian government will have the ability to detect and crack down hard on cryptocurrency users (if they're worth the trouble). If the dystopian government lacks the ability to crack down like that, the dystopian country has almost certainly lost the technical capacity for widespread internet, making cryptocurrency moot. And in all cases, there are better alternatives to whatever problem cryptocurrency is meant to solve (e.g. gold bullion, US dollars), except in some very narrow cases.