This quote from "Non Serviam" section of "A Perfect Vacuum" by Lem also hints at future stochastic parrots argument.
The machine will employ, as the need arises, the pro-
noun "I" and all its grammatical inflections. This, however, is
a hoax! The machine will still be closer to a billion chattering
parrots—howsoever brilliantly trained the parrots be—than to
the simplest, most stupid man. It mimics the behavior of a man
on the purely linguistic plane and nothing more. Nothing will
amuse such a machine, or surprise it, or confuse it, or alarm it,
or distress it, because it is psychologically and individually No
One. It is a Voice giving utterance to matters, supplying an-
swers to questions; it is a Logic capable of defeating the best
chess player; it is—or, rather, it can become—a consummate
imitator of everything, an actor, if you will, brought to the
pinnacle of perfection, performing any programmed role—but
an actor and an imitator that is, within, completely empty. One
cannot count on its sympathy, or on its antipathy. It works
toward no self-set goal; to a degree eternally beyond the con-
ception of any man it "doesn't care," for as a person it simply
does not exist.... It is a wondrously efficient combinatorial
mechanism, nothing more.
They are valuable the reasons you mention. I'm an avid reader, and sometimes people will ask me a question about a recommendation or what I've read, and I have a complete brain lapse (to the extent it's as if you'd wonder if I read at all). Having a list helps that anxiety. I don't really use the other features, and only settled on Goodreads after the Shelfari "merge".
I do the same with logging film watches on IMDb, which is actually useful because I can visualize exact watch behavior by the timestamps, and using exports I can also query my film history for personal recommendations (select documentaries that are horror tagged I've watched from the last 10 years).