The phrase "show, don't tell" means that you should demonstrate facts in favour of simply stating them. Breathing life into your characters and setting means you need to convince the reader that they do indeed have the traits and characteristics you've given them. Sometimes, demonstrating certain information is the same as just telling it outright: when you want the reader to know Bilbo's family tree, you basically just have to say it explicitly. What you're demonstrating there, though, is that Bilbo has a very large and complex family. If you wrote, "Bilbo has a very large and complex family" at the top of that family tree, well, that would be bad writing. With that said, there's nothing inherently wrong with character pages, but in reality I rarely see them executed well. Firstly, they often don't demonstrate anything. Just stating that a character is nervous and soft-spoken isn't interesting or engaging to the reader; telling them that the character has a secret exhibitionist streak that will be revealed later just ruins the suspense and depth of that trait. Worse, these are often used in lieu of actually incorporating those characteristics into the story - the character in question may be written as completely lacking a personality, and the author is pushing the responsibility onto the reader to imagine them acting nervously. Secondly, character lists often expose weaknesses in a story. You mean to tell me this mother of a 19-year-old son and 18- and 20-year old daughters, who all want to fuck each other, looks like she could be younger than 30 and has enormous boobs? What you have there is not a character so much as an archetype; you could basically replace the character page with "this is your average CHYOA incest story" and convey exactly the same information. Perhaps I'm strange, but if I see something along those lines, I consider it a red flag and assume the story is not worth reading. Such stories do not have even the slightest focus on characterisation, and therefore a character list is not very useful.
Oh, I'm not quite that strict. I consider it a bad sign, but one I generally just ignore if first impressions tickle my fancy in other ways. I don't want to do the boring thing and say "eh, it's just a sex story, what does it matter?"... but sometimes I really am just looking for a straightforward all-the-usual-tropes sex-every-chapter stroke story, and not in a painstakingly planned literary exercise featuring many-faceted characters who have unique strengths, interesting flaws, and deep meaningful relationships. In fact, I suspect it's borderline impossible to combine the former with the latter. You would have to craft your sex scenes such that they push the plot forwards, every chapter, every time, but how many times can you incorporate an earth-shattering revelation about one of your characters while they're fucking? Quite often, sex is just sex. I still won't read your meticulously crafted character page, though, so if the information in it is not also communicated through the story, I will probably give up and read something else. Maybe that's a compromise we can all (grumblingly) agree on? Make your character page if you want, but make sure that your story is engaging on its own merits: your readers should not have to keep a detailed character reference on hand to become immersed in your story.
One obvious difference I see between literature and CHYOA stories is that most people aren't reading full stories here from start to finish. Most people are jumping in and out, threads and beginning and often not ending, and if it's been a while since I've followed a thread, I'm not going to go searching through all the chapters to remind myself whether Wendy had blonde hair or green eyes or a pleasant smile or a tattoo on her ear or a job with the FBI or whatever. I may remember that I wanted to pick up the narrative when it looks like Wendy is about to seduce the man who has a pet alligator, but if that's Chapter 97, I'm not going to go back and re-read the first 96 when I can go back to one particular page and remind myself of the basics. Also, if I'm contributing to a public story, then as much as I want to honor the original intent of a given character, I may not be able to fully sort out which characteristics are canon, which are a bad fan fiction thread, what events have happened, what has not, and so on. I tend to think of things like character lists or scene organization lists as simply a resource -- kind of like a wiki. They're not a substitute for the story itself, but they can help a new reader, a return reader, a contributing author, etc. Or, as some folks in this thread have very validly said, they can be utter garbage and significant red flags of stories to avoid! All's fair!