"Jack Dorsey stated that Bitcoin could fail if it isn't used as a medium of exchange. Do you agree?"

John's answer to this was good, but I think he and I take Jack's statement from completely different perspectives.

I think Satoshi was quite clear that Bitcoin's goal is about ending fiat. I think that was his/her/them's greatest motivation. I think that should be the number one goal of any self-respecting Bitcoiner today. If Bitcoin is not threatening the dollar (after becoming nothing more than "digital gold") then Bitcoin HAS failed. Hard stop.

I think that's probably what Jack meant, also. He was channeling Satoshi when he said that.

If "digital gold" is Bitcoin's future, then I may as well just trade all my Bitcoin for physical gold right now.