It's the same opportunity cost whether you spend from your BTC account or your USD account! You're choosing between "should I buy a phone or 0.1 bitcoin with these dollars?"

I think the presence in the market of an asset that many people believe is continually underpriced would have a general effect on spending, not just on the utility of that asset as a medium of exchange...

>> It's the same opportunity cost whether you spend from your BTC account or your USD account!

Only if obtaining BTC is frictionless and fee-free, something far from universal.

> the same BTC might buy 10 phones in a few weeks.

Which is kind of crazy and defies all logic - cryptocurrencies can be manufactured without any limit, even Bitcoin can be cloned and rebooted, creating a new currency space/ledger that's fresh.

You can print out a piece of paper that says "TEN US DOLLARS" on it, but if the corner store or the bank won't take it it isn't really the same as $10.

Will you buy pizza with BTC right now?

Yes? Being BTC doesn't change the value of it.

When you buy a pizza with USD, do you think "hmm, maybe I should invest this into BTC instead?"