I can name a lot of counterexamples, however most of them are illegal under US federal law so it's a bit of a moot point.

There are legal counterexamples, but the majority that come to mind are equally well-served with fiat. If you ask me to come up with a good, legal reason to hold cryptocurrency, I may well tell you that there is none even if there are a few marginal situations that justify it.

See PurpleRamen's comment above. Blockchain != cryptocurrency.

For blockchain, there exist some good (and legitimate) applications.

Cryptocoins otoh... lots of gray area there. If not outright Ponzi schemes.

I hope some day, some crypto coin(s) will fulfill their original promise. But that day is not today.

Distributed blockchain applications are normally unnecessary when they are used though, and absolutely overkill when applied with distributed proofs. Very often a network only needs a secured channel to operate, which can be established with much lower overhead than a blockchain. Currency seems to be the only application that would respect such extreme security measures, and that's really only highlighted the low throughput and capacity problems.

I really do feel the same about blockchains as I do about cryptocurrency. Both have extremely limited applications that appear marketable and attractive to nerd-adjacent circles, but only show their drawbacks once fully invested.

The intention behind creating a blockchain (or even some cryptocurrency) is pure in it's inception. The application of both technologies is so messy that I would recommend most people stick with simpler options.