that comment listed a lot of things that maybe blockchain could theoretically accomplish and no tangible accomplishments at all

I am not aware of anything on your list that I would call a real tangible success.

Proof of work crypto currencies seem like they are currently a net-negative because of the energy consumption. What’s the benefit to society that has already happened?

For AI better speech recognition is widely used and has a ton of benefits. For example nearly all radiologists use voice dictation in order to write faster/better/more reports.