> Why do you use cases need a blockchain at all?

Your example is one of a physical good. Of course you don't need an NFT to display a card physically. But what if you want to display it digitally? Your best option at this case is to take a photo, upload it to the web, then the consuming websites can hire people to scrutinize a bunch of grainy vaccination card photos from their users. Meh.

On the blockchain, you'd have an NFT representation of your card, and its origin (i.e. which authority gave it to you) could be easily programmatically tracked.

Obviously, vaccination cards aren't the best example, because COVID-19 is a real-world virus, not a computer virus, so it's doubtful that digital applications will care much about your vaccination card. But you get the idea, hopefully.

> Or, you could give HN your reddit username and HN could query the Reddit API if you’re a moderator…

This is the N × M problem.

> …and by doing the API requests could find out if that privilege is still current and if those subreddit’s stats match HNs criteria for “trust”. Time and trust seem rather relevant to me. Would you want reddit “moderators” like u/violentacrez in perpetuity have privileges on HN and other forums?

We solve this in the real world by putting expiration dates on licenses and badges. Is that perfect? No. But the benefit of portable certifications dwarfs the costs of the occasional expired or revoked cert.

In addition, NFTs are just code. You could easily include a URL with each NFT, which would point to some endpoint that responds with "revoked" or "expired" or "active". Best of both worlds.

> In a way individual homepages/profiles and a standardised API solve the N×M problem of APIs and could solve as a digital strongbox for your use cases of common information and other acquired signed trinkets.

Sure, that could work. But that standardized API does not exist, or if it does, it's clearly not being adopted, so it's a moot point. Where is the Indie Web in terms of adoption?

IMO HNers often focus too much on the merits of a particular technology, and not enough on the adoption. Often it's the case that worse technologies win, because they enjoy network effects that allow them to grow quickly and then maintain their lead. Again, look at HTML, CSS, and JavaScript -- hardly the best tools to build the web on, but that's what we've got, regardless of the fact that other tools "could" solve the problem better.

You're also neglecting the fact that blockchains are decentralized, but the web is not. The web is based on renting. Renting hosting from some other company, renting space in some company's database, etc. It's fine for today of course, we all do this and it works well.

But the blockchain and NFTs are about improving digital property, and one major improvement is moving from rental to ownership, as I pointed out in my original comment. No company can delete your "backpack" of NFTs, or shut you down because you're a sex worker and they think that's immoral, or tell you who you can and can't sell your items to. Sure, the authorities can try to track you down and punish you after the fact, but that's how things work in the real world, and getting the digital world to that point is the goal here.

For various reasons, this is catching on with NFTs in a big way that it didn't and won't with the Indie Web and other efforts. Adoption matters.