I am pretty anti-crypto generally but I feel compelled to reply to your maximalist position that there is "no practical value whatsoever, current or potential" to blockchains. The one use case I have seen for blockchain that is real is that cryptocurrency is great for moving money around the world when governments or banks maybe don't want you to do so. At the very least the experience of sending crypto is about as annoying or a little bit less annoying than sending a wire, and you can avoid all those pesky AML/KYC requirements that banks and payment processors impose.

I am not suggesting that this isn't ethically fraught -- of course it is. But one can imagine uses. I personally have known a couple people who fled Syria during the civil war, and bitcoin was a useful way to pull money out of the country, and much less dangerous than carrying a suitcase of cash.