That's an unusable currency that doesn't allow for any type of long term planning because volatility is a terrible quality for a currency to have. The inability to plan long term is a death knell for any economy.
And yet, long term, bitcoin has only ever gone up while USD has only ever gone down.
Yes, there is a large amount of short term volatility in bitcoin, due to the fact that it is a tiny market with a tiny number of users. A single user with a large enough stack has enough power to move the market enough to trigger a bunch of bots or stop losses or whatever, resulting in significant price shifts. As a market grows, this becomes less possible, and with far greater numbers of buyers and seller clustering up around the current market price, then volatility lessens dramatically.
Using volatility as an argument against why bitcoin cannot scale as a currency is completely missing the point that volatility is inherent to small markets and assets.