It’s not a “bitcoin dollar”, that’s your first misstep. Bitcoins are broken into fractions...decimals. So at the current value of XXXX dollars per bitcoin, it only costs you .0002 bitcoin for a coffee, plus a minor transaction fee. No different than credit cards, the store usually picks up the transaction fee.
Looked into accepting bitcoin on my site a few years ago. No risk to vendor, funds deposited to your account (value at time of sale) just like credit card payments. Revamping my website would have cost me in the tens of thousands but that was highly situational and was due to shopping cart / credit card processor...etc.
That means at this point Bitcoin's only "value" is as a speculative instrument. Its volatility makes it effectively useless as a medium of exchange because it has no stable price structure. It's the "greater fool" theory writ large and it cannot end well. The announcement that CBOE is going to start trading bitcoin futures is only going to pour gasoline on the fire.