Bitcoin network is constantly readjusting mining complexity, so that every new block will be mined in approximately 10 minutes. Then, they substitute the notion of time with the sequence of Bitcoin blocks. Yeah, well done!
Bitcoin proponents are becoming more and more insane.
Or is it the detractors that are becoming more and more insane? Perhaps it's both. There are so many detractors who seem to have the need to go "hurmph!" every time someone mentions Bitcoin, and often times they have knowledge gaps that destroy their credibility. In every Bitcoin related thread here on HN, there's tons of detractors who make ridiculous claims around the utility and mechanics of Bitcoin that it's hard to take them seriously. Why are they so invested in shouting down Bitcoin in the first place? If someone doesn't like Bitcoin, they can simply not use it. There's nothing wrong with healthy criticism, but it's there's an air of emotional insecurity in these people that makes me wonder whether they're former Bitcoin supporters who got burned after 2017 because of their misconceptions.
It's always been like this, I'm not sure what you mean by "becoming". According to this article, the concept comes from a series of papers from the 1990s.
EDIT: To be honest, knowledge of the hash of a block can be used as a proof that something has happened AFTER a particular event (similarly to a picture of a hostage with the newspaper).
But you can't prove that something has happened BEFORE a particular event using Bitcoin hashes.
Also, this "feature" is unrelated to Bitcoin being a cryptocurrency. You can have cryptocurrencies without "global time" (e.g. NANO).
Yes, you can do it if you put the hash of a message INTO the chain as a transaction (I think they do something of this kind). But in this way you will share the limits of the Bitcoin network. They claim they do it in some efficient way, though. But I wouldn't trust it without checking their algorithm.
Anyway, any other "linear" blockchain (e.g. with PoS consensus) can do the same work. No wasting of resources is needed.
Bitcoin proponents are becoming more and more insane.