I agree that because of the lack of controls it will be more volatile than other currencies, but I think volatility will at least reduce to something like gold once the majority is mined. It's volatility is partly due to the difficulty increase and reward halving part of the protocol. I.e. the part designed to reward early adopters. Which was necessary to bootstrap it.

It's a speculative game for the first maybe decade or two. As the bitcoins gradually leave the early adopters as they cave in to whatever price is worth it for them there are bubble cycles. Once there is more general adoption, it will settle down though. As people gradually start to think less in e.g. Euros and consider not changing directly into local currency, but just to hold some for their day-to-day transactions because they are particularly useful in certain circumstances.

Once it's passed a tipping point they will be more useful in more and more situations, to the point that it's easier to just have your smart phone and cursing cash or credit card only places. I'm sure there will be retro hipster bars that take cash only in the future.

Anyway, as for the remaining volatility, it may just be that bitcoins serve as gold and another somehow regulated cryptocurrency serves as ordinary money.