That argument needs some quantifying. Yes, in the beginning of the mania (like I believe we are just starting), it is wildly volatile. We’ve just seen 2 pretty good sell-offs in less than 3 weeks. This Alt-coin/Blockchain technology is not even a toddler yet and with less than 1 in 10,000 people having a BTC address it’s likely that we have a good 2 – 4 years more to go before the bubble pops. Once it pops, (and it will just like the housing market in 2008), the mean will return and this will stabilize it to behave more like a currency. In fact, it should become very stable more so than fiat currency which continues to be devalued faster and faster each year and subject to manipulation through central banking and the IMF.