For doing business in bitcoins, this is a minus, here no one will argue among those who did real business (they are all interested in a stable means of payment). But you must not forget that the "intrinsic" volatile value of bitcoin lies precisely in the fact that it is completely independent of fiat.
What you're saying is it's volatile because it's independent of fiat. You're right bitcoin is but that's not a good sign for some people taking their first steps buying cryptocurrency because they're going to be unprepared for worst case losses.
Volatility is destructive to price stability and general business usage, its a discouragement often stated but also BTC itself has advantages over plain cash and the costs to handling that. I've always thought Bitcoin will fail if it ever fails to handle the needs of the smallest entities in the economy, whales is a fine thing but they dont support an economy despite their size its often the revenue which matters in a business for economies of scale and other considerations.
Bitcoin is sustainable is probably most easily considered by how easily anyone can use it for the most normal amounts, I was bearish in late 2017 for this reason but its not been as bad since that peak and some of the backlog was deliberate. Prices rising constantly is a form of volatility and imbalance, also why I dont think we keep gaining without some pullback.
That's the worry because similar to others I'm believing volatility=discouragement. Investors are making huge profits because of volatile cryptocurrency price so it's working to be encouragement for some investors and discouragement for some.