what bitcoin is as a technology isn't as relevant compared to what it is as a means of exchange. people don't care about the protocol, they care about the value bitcoin provides to them. To make technology the most important sales pitch of a currency is an ideological choice on part of the people pushing for bitcoin adoption, not some sort of obvious or intuitive insight.
> Constrained supply means protection against inflationist central banks.
This again, is a non-issue for consumers and everyone who isn't ideologically invested in crypto-technology. As long as you don't park your money under the mattress for a hundred years but actually spend it the stability that existing currencies provide is sufficient (and much preferable to the volatility of bitcoin.)
> A currency that isn't used to commit fraud isn't very useful. Therefore, to say that Bitcoin has failed because of fraud is dishonest at best.
That's obviously not the point. What is worrisome about bitcoin isn't that it's used for fraud at all, it's that fraudulent activity and weird con-like schemes constitute a significant, if not majority of activity. Which isn't surprising if the two points above are taken into account, it simply is not particularly useful for anything else.