Erm, no, many understand very well what blockchain is and it's definitely not opaqueness what they accuse it of. But everybody can choose their own strawman to fight, can't they.
Give me some bitcoin and i would not know what to do with them except changing them back into money.
You can’t think of any situation where you would want to share access to and control of data with multiple untrusted third parties, where you would need to guarantee not only that data modifications are only executed in an authorized fashion, but also that no previous modifications have been reversed?
The list of use cases for that capability is not limited to “money laundering and tax evasion.”
Do you mean a cryptographic signature? Been doing those for decades back in email chains and newsgroups. Each message could contain the prior messages and their signatures. What’s new was assigning a currency to it.
But you can't rely on this approach to ensure that surreptitious deletion of old messages or threads is impossible. Not every old message in a newsgroup will be duplicated within new messages, and threads will typically not reference each other.
If an old message or a separate thread provides necessary context for interpreting a new message, the maintainer of the newsgroup or the email server has the ability to change the meaning of a conversation simply by deleting messages or threads. Or the owner of a relay server can block certain messages from propagating. You still have to trust these people.
Email is itself very decentralized, at least in concept, with every new email being copied into multiple accounts on multiple servers, so censorship like this is more difficult. But you can imagine how in a more centralized system (like Facebook or Twitter or HN itself) history can be rewritten by the entity hosting the conversation simply by their deleting messages. If all references to the unwanted messages are also removed, then for all intents and purposes, those messages would never have existed. Gmail is dominant enough that you can imagine Google being able to assert this power over much of the email traffic that currently exists.
A blockchain ensures that every modification to the shared state follows rules that all participants in the system agree upon. No modification to that global state can occur unless those rules are strictly followed, and because all participants receive all details of every state modification, the entire history of the global state can be replayed at any time by any participant such that surreptitious deletion is not possible. There is no other technology that I am aware of that is able to systematically prevent surreptitious deletions.
Cryptocurrencies are not the only thing that is new, and they are not even the most important feature of blockchains. Cryptocurrencies function as an incentive mechanism to ensure that there are a healthy number participants validating the state transitions. They can improve the reliability and security of a blockchain system, but there are blockchain systems that do not depend upon them.
Every single concrete example I can think of personally would work better with a normal database and some kind of Auth scheme which does not involve Blockchain, but maybe I'm just thinking of the wrong usecases?
Sounds like tax evasion/money laundering with extra steps to me.
You could call it justified tax evasion, maybe. If I'm being generous.
My assertion is quite different: that people familiar with basic computing technologies have a natural intuition for web technologies, which brings with it comfort and trust, whereas this is not true of blockchain and cryptocurrency.
As I said I was excited by the potential of blockchain and crypto, and would welcome it being widely adopted, but I suspect this factor is a major barrier. I’d welcome evidence to the contrary, not sneering.
What is opaque are all the various bizarre schemes to try to turn them into something useful and profitable, because they really aren't good for that much. (Non-zero. Definitely non-zero. But not really that much.) You either have to stretch them into a space they aren't really good for, or all but create a problem they can solve, but essentially doesn't otherwise exist as a problem. This is where a lot of the complication lies. NFTs, for instance. Drop-dead simple technologically, really. The confusing part has always been, why would anyone spend that much on a fairly crappy picture of a monkey? There's multiple layers of "wtf" to unpack in that question. But the technology itself permitting it isn't that complicated.
How to I add some data to a blockchain? What is a blockchain?
I vividly remember that time in 1996 when I had to explain to my schoolmates what a _webpage_ was. (Whithout really having an internet access yet.)