Save scumming on dialogue checks has been discussed in the past and no wonder: with the bounded accuracy of BG 3 it is a very hot topic, since even characters which are supposed to be extremely good at a task being able to fail with a little bit of bad.
One claim that has been made is that the game (like Disco Elysium) is supposed to have your back when you fail rolls. I want to use this thread to discuss in some detail examples of where this is true - and to be honest, I don't have any. In my experiencing a failed skill check usually has you get a lesser reward or gets you in a fight. Are there really cases where something happens that is as good/interesting as success? There is one with a failed fight, where
Lost Light: if you fail to stop Isobel getting kidnapped all the harpers and refugees die. It's admittedly an interesting variation of the Chapter 2 story, but in terms of gameplay it strictly worse - you miss out on several quests, potential companions and XP. Story wise it is interesting though.
To give an extreme case where I think the game does not have your back:
You can get the Awakened buff from the Zaith’isk in the Creche. That buff is absolute massive - being able to use Perilous Stakes (and later Black Hole) as a bonus action and still attack is really busted, especially on a class like Wizard which has limited options for using bonus actions otherwise. To get it you have to make a few saving throws. If you fail you get a permanent stats debuff instead.