In most transaction, the third party also act as an insurance, a safety. If something goes wrong, the third party is supposed to be here to make sure everybody got their fair share without the need to take legal action, which can be difficult to near impossible sometime.
If I get scamed, does the smart contract allow a chargeback ? Who is going to make sure I was scam and not abusing ? etc.
What insurance would you need when sending a Bitcoin donation to a site where thousands of researchers already benefited by retrieving scientific journal articles?
I didn't write, "cryptocurrencies will replace all third party payment systems." I gave a single example of a situation where third party payment systems don't function and Bitcoin does.
They just haven't gotten around to it yet. The decentralized nature of cryptocurrencies increases the number of entities that need to be pressured, but doesn't make state-level actors completely powerless.
Since stopping cryptocurrencies is harder than freezing third party payments (evidence: see Wikileaks), this is a single, narrow example of the usefulness of cryptocurrencies. Researchers get the convenience of sci-hub's frontend for longer than they would if sci-hub had relied on a third party payment system.
Finally, there are a lot of good reasons why in democracy we vote per-head and not per-share. It's a big thing, but that is also being dismissed by cryptocurrencies.
They've forked before they could be forced to again.
New: state-level actor(s) cannot stop an organization from receiving payment merely by forcing your third-party payment processor to freeze funds/stop payments.
Example: sci-hub. If they were receiving payments through Mastercard/Visa it would have almost certainly been frozen long ago. However, since they (apparently) get funded by receiving Bitcoin, they continue to operate. In the meantime, grad students and professors get the convenience of using sci-hub's interface to easily retrieve journal articles.
Even if sci-hub eventually gets taken down completely (or a researcher finds a catastrophic bug in all cryptocurrencies), the total time during which sci-hub served documents funded by Bitcoins was a benefit to society.
ETH allows fancier transaction scripts than Bitcoin, but the same argument holds-- a state level actor cannot just stop the contract from being executed simply by putting pressure on a third party.
Based on this article, I'd say there is value in ETH just as there is value in writing a complex, multi-threaded application in a memory-unsafe language. It's a bad idea, but for some special cases it may be better than doing nothing at all.