This is a fine comment but is a little like saying "the best way to understand elliptic curves is not to study elliptic curves", which, sure, a first course in abstract algebra will be more profitable for designing entirely new constructions (or evaluating them from first principles) --- which most practitioners don't actually do.
Some people are just interested in curves themselves. That's the point of an article like this. If you want to learn how to build a signature scheme, there are good sources for that as well.
I think it would be more precise to say "The best way to understand elliptic curve cryptography is to study discrete log cryptography, not to study elliptic curves".
There is a tremendous amount of ECC tutorials that walk people mechanically through the group law, I think I've seen a dozen new ones posted on HN in the past year. I don't think I've ever see an article on actual elliptic curve cryptography (beyond briefly explaining DH, as this one does).
Like-- say the article were instead explaining elliptic curves as part of factoring, how would it differ? (This one would omit the DH part, but many don't even have that.)
Personally, I think they're not that useful from the perspective of cryptography. This level of article doesn't bring you to number theory insight or anything like that. They are useful for slavishly coding your own ECC thing without any understanding, but the results of doing that are inevitably totally insecure toys. Hopefully that isn't something "most practitioners" are doing-- hopefully they're linking libsodium or something. :)
If you like it, great! I think I provided a pretty useful curriculum that someone could self-study if they wanted to actually dive deep on the cryptography.
They're not meant to be useful from the perspective of cryptography, in the same way as learning textbook RSA is not useful in that sense. They're useful in the sense that people want to have some faint clue of what's happening.
Maybe it's just a difference in how I look at it, but knowing what group law is doing is not a useful clue to me.
From being able to apply group law you couldn't predict the properties or (most of) the vulnerabilities. (or even performance, since these things don't generally cover projective coordinates).
At least the way I see it is if you asked about how a spell checker worked, and then I set out and explain how a digital adder circuit works from the gate level. You can't build a spell checker without adders yet you wouldn't be informed. :)
This sort of thing also strikes me as the sort of thing that more "feeling of understanding" without creating much understanding. I seldom think it's good to do that, though it isn't always harmful.
But learning styles is certainly something that differs a lot between people, so I certainly don't think my experience is universal by any means.
I can say that personally learning to ignore the machinery made my understanding grow 100x faster and directly resulted in constructing more than a few publishable (and widely deployed) designs.
Some people are just interested in curves themselves. That's the point of an article like this. If you want to learn how to build a signature scheme, there are good sources for that as well.