Automatic tagging with meta tags from the article
This one makes perfect sense!
I use Raindrop frequently and have a vast collection of bookmarks, hence I rely significantly on tagging. I couldn't use this tool without a significant amount of tags, however this process makes me waste a lot of time.
I believe it would be simple to implement: many articles include tags that would be easy to get. I have done it myself (it's not ideal, but it works), but it's not very stable; occasionally the code fails (I suspect I'm being blocked by the server, though I'm not above the limit of calls per minute), and it takes a lot of effort to change and maintain...
For me, the suggested Tags don't really work.
It really depends on the page, if they put Keywords in it.
At least it should suggest some tags from the same site which you already bookmarked.