They say you should write to your audience and this feels like the author did and it’s targeted at an audience - that, well, is not HN.
I wish it had been targeted at HN - as then I would have read it. But after the first couple of sentences I gave up - and waited for people with more fortitude, to read the doc and report back here. (Thanks to everyone who did that.)
I get there are many others ways to skin this... However the author is at least trying and providing. As a prior comment stated, there are a lot of very good people in the security/crypto/dev realm in this very thread that have provided some awesomely D-bagish feedback.
Easier to use does not imply better in this space. In fact it may be worse than not providing a product at all because it encourages people to think they have a secure channel when in fact it's trivially breakable.
But in this case it's popular because it's easy to use than other systems and not because it's more secure than other systems.
Sometimes you just have to hit the thing with a bat to get attention.