Yeah, the little "affect the story/world fiction" was the best thing about them (though I believe @Oofta disagrees). They didn't have a straight quantifiable mechanical benefit, but could be used to create story threads that could either abbreviate a sequence (finding an inn, finding food, locating the black market) or initiate one, depending on how the player and DM wanted to RP it.
Early on in a 5e campaign that began in 2017 one of the players seemed upset I didn't have the NPCs react a certain way and said "but I'm a Pirate". I immediately changed the reaction of the NPCs and I think it added a lot without it being mechanically powerful. Just something for the players to hang their hats on when playing their PC. I loved that backgrounds weren't just a simple pile of numbers.