>What cryptographic standards have come from cryptocurrencies?
Zk-STARKS, which are fairly revolutionary and completely unknown outside magic internet money dudes. Non-trusted setup ceremonies and the newer Zk-SNARKs are also pretty much crypto-only. Bulletproofs arguably as well. Maybe verifiable delay functions; not sure of the history there. Most cryptocurrency engineering is evolutionary, and it's the combination of things (Mimble-wimble etc) that makes it worth something.
On the non crypto side, there are novel consensus algorithms, interesting data structures and contributions to distributed computation in general.
There's lots of social problems with blockchains, including carnival barker types overhyping things they don't understand. You could have said the same things about the internet in the 90s. The technology is pretty interesting, and making the things do useful work is one of the few actually innovative areas in software engineering right now.
There's lots of obvious places for this sort of distributed, trustless database that aren't just magic internet money. DNS is an obvious one. Identity is another one. Provenance of food/wine/art is another. Pretty much any place where database disintermediation is desirable, which is almost everywhere.