You're making a fallacy sui generis.
$USD in circ is $2.4T.
The market cap on BTC, as measured in $USD, is almost exactly half that amount.
BTC is not a preferred currency in the US because we are the home of the Dollar.
But an 6-bedroom apartment in Beijing's CBD? Or a 7-bedroom mansion in HK's Mt. Nicholson? Or an iron-front faced heritage house in Singapore's Emerald Hill? Bought with BTC, or BTC converted into anything but $USD.
“You’re making a fallacy sui generis.”
And your fallacy is using exceptions as the rule
$2.4T is the currency in circulation. Most of the transactions are no longer done with cash but with credit and debit cards and they’re about $100 trillion a year.
Transaction done with Bitcoins to actually buy stuff is a tiny , tiny fraction of that, and yes most of it is done in countries where their currency is not trusted or to avoid the law, but even that is a tiny amount.
Most of the activity with Bitcoins is speculative - buying and selling it for currencies to profit from its movement.
By the way, I’m not at all against Bitcoin, in fact I own some miners, but I very much question that it will ever become a true currency used for everyday commerce. The main reason is its finite amount. Because of that it tends to be deflationary, hence people are more likely to hoard it than to spend it.
If the total amount were allowed to increase by 3-4% a year, as Milton Friedman proposed, then it would have a greater chance of being more widely used.