It could be kind of lame to poke fun at a site that I don't use (anymore), but I find this funny enough to share: Goodreads has started changing and updating their site last year, but apparently they've broken a ton of things in the process, and now they've published an announcement with the list of 12 bugs they're (supposedly) trying to deal with.
In short, literally the most essential functions aren't working. In the iOS app some people can't shelve books. On Android people can't see all reviews. On desktop the search and sorting are completely random, the default editions that represent each book are also apparently random, though it seems the selection favours the editions in any language other than English, preferably also in a non-Latin script. The database is borderline impossible to navigate.
So if you search for Harry Potter, the first result is Random Harry Potter Facts You Probably Don't Know: 154 Fun Facts and Secret Trivia. If you open the page of William Shakespeare, the first books that are presented to you are Romeo and Juliet in English, Hamlet in Italian, and Macbeth in Arabic. And after a while instead of showing his actual plays, the site just lists weird collected editions such as Romeo and Juliet; Hamlet; Othello; An Index (The Works of Shakespear, Vol. 8) by some scammy publisher that prints PDFs from Google Books.
I've spent enough time on GR to see how it's held together by duct tape and inertia, and now it really seems to be crashing down. Still, kudos to the admins who are keeping up with the recent trends in technology, such as actively ruining your website, as also seen on reddit and Twitter. In fact I'd say GR has better chances of actually dying (i.e. having a massive user drain) than the other two sites.
Is there anyone here who's still active on GR? Not trying to judge, but I really have to ask -what's making you stay there? Are the alternatives too lacking in book data/users?
So i actually only started using it this year to track a reading challenge (finally started reading again after years out of the habit), but my wife's been using it for years. I think she uses it because it has a massive record of all of her books read and reviews.
When I started using goodreads, I decided to go through and check off books I had read in the past to add to my "library". Note that when you do this from Goodreads' initial setup, it doesn't give you titles, only the covers. A while later my wife was looking through and asked "why did you list that you read the sheet music for Harry Potter and the Goblet of Fire?" I hadn't, but it happens to use the same cover as the actual book, so I would've had no way of knowing that was what I clicked initially. Other things I mistakenly listed myself as having read were the Game of Thrones RPG book, a pop-up book of Harry Potter and the Prisoner of Azkaban, the (World of) Hunger Games (Companion Guide), and I'm only remembering the high-profile ones.
Similar reason for me, I've been using it for years and it has a record of all the books I've read and when. It's easy to just pop on the site when I finish a book and record it.
Recently I've requested my data from them and got a zip full of stuff, the books seem to be in there so in theory I could migrate to another service. Or simply use any app that can record a timestamp and a piece of text, or even just a text file.
For this basic purpose it's true I don't need GR, I know which book I'm reading, I don't need to look it up. But GR has value in looking up books by the same author, books in the same series, seeing what people think of a book or series so I can prioritize future reads, following an author etc. There is value in GR, too bad it's being squandered.
I took that zip file and imported it at Storygraph. That site isn't perfect either but at least it's building up instead of falling down, and seems to have heart. Also its recommendations, while hit and miss, are a lot better than what Goodreads has offered in the last couple years.
The two things I occasionally go back to Goodreads for at this point are the list of releases by authors I'm following, as you mention, and an FSF book club I'm in over there. That said I haven't bothered tracking my books on GR for a while now. I really can't see it turning around any time soon, especially now it's Amazon owned, and Storygraph deals with that aspect of things very well.
I've also seen Bookwyrm mentioned around here lately as a Fediverse alternative. I'm not familiar with it or its features, but it'd bear looking at for comparison.