Even if places accept bitcoin they almost universally price their goods in $/€/£/.. meaning that bitcoin is only a transfer mechanism. So it’s not really a “currency” in that situation either.
I mean if somebody accepts precious metals, jewels etc. as payment in lieu of actual money that doesn’t mean those things suddenly become a currency.
When I said "most successful" I didn't mean it was a complete success, just that this is the best we've done without a state. Currencies are hard, history is full of them failing. Maybe when an asset is liquid enough, it becomes like a currency.
I mean if somebody accepts precious metals, jewels etc. as payment in lieu of actual money that doesn’t mean those things suddenly become a currency.