I've studied a lot of failed and successful currencies over the years and came to one unshakable conclusion: The sole criterion for the viability of a currency

I've studied a lot of failed and successful currencies over the years and came to one unshakable conclusion: The sole criterion for the viability of a currency is acceptance. The backing of a nation doesn't decide it. The silliness of it doesn't matter. Not being granular enough won't stop it. Being illegal doesn't matter. Physical existence doesn't matter in the slightest. All that matters is, "Can you buy stuff with it?" Everybody calling crypto a scam are simply in denial. Are there scam coins? Of course. But you can buy a lap dance in Portland with BTC.