Earlier quoted context omitted.
No, the volatility has been entirely in BTC. Volatility should more accurately be measured against actual real-world goods that you can buy. Since pretty much all actual goods are priced in currencies other than BTC, with the BTC price merely set based on the current exchange rate with the currency that the goods are bought at, it's BTC that's volatile, not the USD. This kind of volatility is actually really harmful…
> It's pretty dumb to actually spend bitcoins if you could just hold onto them A similar question can be asked about USD: why would you ever save it instead of spending it immediately, since it's only going to lose value over time due to inflation? Of course, the difference right now is that the deflation rate in bitcoin is much higher than the inflation rate in USD. But clearly, if bitcoin ever becomes a major curre…
The answer to this question lies at the heart of why economists generally believe a little inflation is better than no inflation nowadays. That little bit of inflation makes it more attractive to invest money in things that increase one's ability to generate money in the future instead of just stuffing it under a mattress. That makes the economy as a whole more vigorous, which means everyone tends to get more wealthy in the long run.
As for deflation in Bitcoin: Since the total number of BTC that can ever exist is asymptotically bounded, but potential economic productivity of a population of humans isn't (as far as we know), there's really only a few scenarios where BTC deflation might level off, and arguably all of them fall under the category of "economic crisis".