I agree with you. But imagine that a secondary ecosystem emerges because of these crazy cryptocoiners, who start using crypto for everything (just out of princ

I agree with you. But imagine that a secondary ecosystem emerges because of these crazy cryptocoiners, who start using crypto for everything (just out of principle) (see https://99bitcoins.com/bitcoin/who-accepts/ https://99bitcoins.com/bitcoin/who-accepts/ for viability). They also insist on getting paid in crypto (not every country puts capital gains on crypto). This basically means we could have a small parallel ecosystem. Imagine this thing growing to a few % of all transactions. Now the question comes to people holding fiat: are you sure your fractional reserve money will keep its value? Only a small percentage of fearful people could cause serious issues for that fiat system. So I agree that you are right for now. But I wouldn't rule out the possibility of it taking a shift in the future.