There are a significant number of games where data-mining or testing made specifics available that the game developers had not, like deriving formulas or giving specific rule mechanics that the game developers did not. I really wanted someone to make that available.
I like Nova Drift, a roguelite Asteroids game where one can create a ship build. But to design a build, one has to know how certain effects and weapons interact. You could do it yourself, but if you're wrong, then maybe a 30 minute build goes bad because of a bad guess. Material on Reddit or the game's fandom wiki often details specific mechanics that the game itself doesn't document for users.
A lot of people spent time deriving Fallout 4's damage mechanics. Those are kind of important to making the decisions in how to craft a build.
Now, I realize that you could argue that there are cases where withholding information can be part of the game's experience, make it feel more immersive. But...you don't have to seek the information out in those cases. There are times when I've regretted looking at spoilers in a game. But I can think of a great many more cases where I've been exasperated because nobody has documented something that I really would like to know. For me, one of the benefits of deferring game purchases is that people have already gone through and documented a lot of the stuff like this on the game's wiki, and you can dig it up if you want it.
For a recent example, yesterday, I was trying Balatro, a game that I've seen people on this community and other places wax enthusiastic about. It has the "Magic Trick" Voucher, which has a description that just says "allows playing cards to be purchased from the Shop". What does this mean? Does it create some new field in the Shop to contain those cards, in which case there is no drawback to the purchase except the price? Or does it replace some existing Shop offers, in which case there are excellent reasons to not want to purchase it, since it'd require one to consume more Rerolls in order to get as many non-playing-card offers? If I go to the game's Fandom wiki, it actually says what the thing does, which is the latter; it gives a certain weight to playing cards showing up; offers for them replace offers for other types of cards, like Jokers:
With the Magic Trick Voucher, playing cards are given a weight of 4; the Illusion Voucher makes playing cards enhanced 60% of the time.
Yeah, I could, for each card and interaction in the game, buy it and find out and be disappointed if the thing doesn't work the way I guess that it might, then try to memorize or personally document those, but I'd rather not do that; that's a slog. There are certain games where one has no realistic way to deal with a new enemy the first time one runs into them rather than dying to obtain knowledge to use that knowledge in future runs; generally, this has not been considered desirable by reviewers, and I agree with them. I'd rather have the mechanics described precisely. The game designers didn't do that, but players did.
That's not a problem for board games, because the players are the ones who have to carry out the rules. There are no "invisible rules". If the written rules are ambiguous, then players are going to have to make a decision themselves and can play with that rule.
But with video games, the documented rules that the players see and the actually-enforced rules of the game can differ, because the computer is enforcing the rules. Documentation can be incomplete, misleading ("flavor text" that inadvertently implies a particular behavior is a common offender here), or even outright wrong as to what actually happens in a given situation. That can be really frustrating in games where planning ahead is important.
And then there are devs/games like Nolla/Noita which specifically included a nice little message for data miners which asked them to keep all the gained secrets a secret until a certain date with a reward for both them and the community if they did and who would have guessed: they did!
And now they are immortalized inside the games credits!