Hmm. I think not using standard protocols but an ad-hoc API may result in vendor lock-in, which yes, is a bad thing (though it doesn't mean it's generated). For example, one of my clients has backups in AWS, and he initially asked me to upload them using standard sftp, but then we saw the bill for using the sftp add-on and had to immediately rewrite the uploads using the free but vendor-specific CLI.

Regarding the docs, I see they put them in help texts, which tbh isn't that bad, but indeed duplicating them online for convenient search would be obviously better. For my library, I put the docs all in the readme like many libs did in early years of Node.js (and I liked the docs that way), without an extra documentation website, though I have a landing page showing quick start examples.