Erm... BTC is less stable than USD by every conceivable measure.
http://www.orchardplatform.com/wp-content/uploads/2015/05/bt...
Tell me: would you be surprised if BTC changed in price by 50% by the end of this month? I wouldn't be, I simply don't trust BTC to retain its value in any way. BTC goes up or down, and that's bad for "currencies"
Bitcoin being a globally distributed ledger has the ability to represent shares of commodities and equities. It's why Delaware is considering incorporating blockchain tech.
You could imagine merchants pricing in shares of Apple - and customers paying in shares of oil and Google - to be settled at PoS. Check out shapeshift.io to see how fluid crypto-to-crypto trades can be.
http://www.wsj.com/articles/delaware-considers-using-blockch...
This is not the case for BTC or AAPL. If I get 1BTC today, some new MtGox story might wreck its value before I buy groceries with it tomorrow. AAPL is unlikely to move as much, but it moves around by several percent on a fairly regular basis, and some huge negative news could send it plunging.
I could imagine your scenario of pricing in AAPL and paying in oil and GOOG in a technological sense, but I have a hard time imagining anyone actually doing it.
In Kenya people trade in cell phone minutes (MPESA). It's not a huge stretch to imagine trading in units of energy or other commodities.
It seems to me that having an instant settlement layer challenges the need for currency as an intermediary.
What? Do you change all of your savings into stocks or bonds each month?
Currency is the best short-term store of value. And "short term" means anything I plan to use in the next 6 months (My emergency fund will last 6 months without me being forced to touch my bonds or stocks, giving me breathing room for when to liquidate my long-term savings.)
I trust cash to be stable in the short term, even if it loses value long-term. I can't trust BTC as either long-term or even short-term storage.
BTC utterly fails at "6-month" storage due to its volatility. BTC has no history for growing (stocks are based on company profits. So as long as companies are profitable, they'll grow). Bonds are strong guarantees for growing: only bankruptcy can prevent me from getting me money promised through a bond.
What guarantees do I have for long-term BTC storage? Nothing. Absolutely nothing.
Short term? Well, again, stability is more important than gains in the short term (which is why my short-term is cash... not stocks).
