The shifting goalposts of this argument have been interesting to watch over the last 3-4 years.

Stablecoins: I remember plenty of commenters being quite certain that volatility made cryptocurrency unusable. And yet a short time later we have successful decentralized stable coins.

DeFi: Just in the past months Uniswap has rivaled centralized exchange volume as a decentralized exchange. It's permissionless composability appears to be spinning off an interesting group of experimental financial instruments.

These are a couple huge concrete examples of successes that make the ~show me something real~ argument difficult for me to accept. Nobody has built skyscrapers yet, but skyscrapers aren't built in a day. We have some pretty solid architecture going up it seems.

And if you've been following the space long enough most of this article is tedious and inconsequential:

1) "For instance, hundreds of links to child pornography and revenge porn were placed in the bitcoin blockchain by malicious users."

This is a tired argument from 2013 which nobody cares about: https://www.wired.com/story/why-porn-on-the-blockchain-wont-...

2) "Also, in a blockchain you aren’t anonymous, but “pseudonymous”: your identity is linked to a number, and if someone can link your name to that number, you’re screwed. Everything you got up to on that blockchain is visible to everyone."

Blockchains have many different properties. Some have more stringent privacy measures than others. Many HN readers are likely familiar with privacy coins employing things like zero-knowledge proofs or ring signatures. Not to mention the burgeoning research into the implementations of homomorphic encryption. How about Harvard putting your genome on the blockchain in such a way where you retain full control over it's rights? Doesn't sound completely useless to me: https://nebula.org/whole-genome-sequencing/

3) "The fact that no one is in charge and nothing can be modified also means that mistakes cannot be corrected. A bank can reverse a payment request. This is impossible for bitcoin and other cryptocurrencies. So anything that has been stolen will stay stolen."

First of all huge amounts of digital theft occurs today that goes unreversed. Also infrastructure reducing errors in cryptocurrency is being improved all the time. Transaction finality has cons but also pros and can be modified. And one can also imagine insurance for these types of losses becoming commonplace.

4) "And then there’s the environmental problem."

This is probably the most legitimate concern so far. All I can say is I hope we get serious about investing in clean energy production as a country/globe. Many things use energy, including cryptocurrency, and that isn't stopping anytime soon whether we like it or not.

5) His complaint that a specific project is not using the blockchain correctly and individuals couldn't explain the blockchain well isn't very convincing.

Of course lots of experimentation will fail. Pets.com didn't make the internet wrong. And even the experts have trouble describing possibilities that don't exist yet. If that isn't reminiscent of the early days of the internet then I don't know what is. If you've seen Bill Gates get mocked by Letterman while trying to describe the early internet then you understand this difficulty.

It's worth remembering that this area is still incredibly young. If you can't at least see the potential then maybe you aren't looking in the right places. Like here: https://a16z.com/2018/02/10/crypto-readings-resources/