Stable is good.
Stable is not good. According to merchant reports, more bitcoin is spent when it is falling or rising than when price is stagnant. Falling prices encourage people to spend because they fear further loss. Rising prices encourage people to spend due to the wealth effect and the nagging feeling that price is bubbling.
Sure, in some magical fairy tale land where you can spend bitcoin everywhere we might be able to cheer bitcoin for being a stable currency. But that fairy tale scenario will create stability. Stability won't bring us to that fairy tale. The road to mainstream bitcoin is going to be bumpy, but that's how people stay interested.