I don't think you understand currencies? There will always be some level of currency-to-currency trading, but the hope is that it will be minor compared to the major purpose of a currency--- using it as a easy way to exchange value. (Which I imagine is what you were referencing when you said "original purpose".)

> using it as a easy way to exchange value

This is what I was referencing. Nobody will ever use bitcoin as a means of exchange if the price of a car today is 30% less than it is tomorrow.

The most important thing with a means of transaction is the stability of its value. Bitcoin will never be stable so long as it is used as a vehicle for investment (aka a commodity).

"Nobody will ever use bitcoin as a means of exchange if the price of a car today is 30% less than it is tomorrow."

Yeah, that's not how it works. Most holders just spend and replenish with fiat.

"The most important thing with a means of transaction is the stability of its value. Bitcoin will never be stable so long as it is used as a vehicle for investment (aka a commodity)."

Volatility is expected to decrease over time. https://bitvol.info/index.html