People actually read cover letters

I have my doubts. I've had more than one recruiter tell me "I don't read cover letters", and even if they are "reading" it, it's going to be a brief skim at best.

In any case, that still doesn't mean that you should be writing them. My point is that it's make-work. It's there to weed out candidates and demonstrate your ability to jump through their hoops.

a cryptographically secured entry on a pubic ledger has some conceivable use.

We're talking specifically about NFTs.