I agree with your statements on fungibility/liquidity, but what's curious is that Bitcoin is actually more liquid than most assets on the planet.
> They will always be inferior to the dollar purely on the virtue that they rely on the value of $USD to exist
As long as you can access / cash out from dollars, yes. Most people don't have this privilege or access to first class financial services.
Usage:
I agree that usage is currently being driven primarily by enthusiasts and speculators, but in the last 3 years its changing fast... Here are some links. https://news.ycombinator.com/item?id=33723425