That coal-mine flood was in Xinjiang, and Xinjiang has now kicked out all its Bitcoin miners, because the only way it's profitable to mine Bitcoin with fossil-fuel power is when it's subsidized, and it was being subsidized. But subsidizing Bitcoin mining is unprofitable for any government, so these subsidy-exploitation setups tend to be short-lived.
90% of Bitcoin mining in the PRC got shut down permanently last month with little warning, dropping the hashrate by half: https://www.globaltimes.cn/page/202106/1226598.shtml. Presumably it will nose back up over the next few months once deals have been signed and the mining hardware has been installed in new places with cheap unsubsidized electricity—necessarily from renewable sources.
I agree with your skepticism about non-currency uses of blockchains. Some people do seem to be using ENS now, and I think smart contracts might become usable eventually, but I'm not confident blockchains will be part of smart contracts as they actually get deployed.
As for the 12-years-into-the-internet thing, well.
The ARPANET started running in 01969. The first version of the FTP protocol we use today (USER, PASS, SOCK, TYPE, BYE) was standardized in RFC 354 in 01972. The "Internet Transmission Control Program" (TCP), featuring SYN/ACK/FIN bits, but 20-bit host numbers (divided into a 4-bit network ID and a 16-bit "TCP address") and 24-bit port numbers, is specified in RFC675 in 01974, and experimental deployments started in 01975. Version 2 of TCP is IEN 2 from 01977. Version 3 of TCP, with a separate IP layer so you could use it for voice over IP, is from 01978. 12 years after the ARPANET's launch was 01981, which is when the Internet Protocol was finally standardized (in RFC 791, IEN 128, replacing the 01980 RFC 760) as a future replacement for NCP. The switchover from NCP to TCP/IP was January 1, 01983.
So 12 years after the internet's launch was, depending on where you count from, either 01981, 01987, or January 1, 01995. Even on January 1, 01995, most of the US still had no for-profit ISPs; the closest thing most people could get was AOL over dialup (probably 14400 bps), which had three million users (1.5% of the US population) and wouldn't let you browse the WWW. AOL added an email gateway to the internet in 01992, Usenet access in September 01994, and web browsing later in 01995, all paid by the hour. At some later point AOL started providing actual internet access (so you could, for example, use telnet and ssh and upload files via FTP).
It was clear to me what the internet's utility was as soon as I got on it in 01992, 23 years after it started. But in 01995 Bill Gates's The Road Ahead dismissed the internet as a primitive precursor to the "information highway" he imagined, so it wasn't obvious to everyone, even 12 years after the switchover of the ARPANET to TCP/IP.
Similarly, the utility of Bitcoin is obvious to me, too, and to millions of other people. I've written about it here before, for example in https://news.ycombinator.com/item?id=27448744.