I would say that it makes perfect sense for dragonborn to have dark vision. But also that it makes little sense for gnomes and arguably tieflings to have it. Fiends live in hell, high you'd assume would be pretty well lit, what with all the infernal flames. I've seen in Pathfinder 2e as well that waaaaay too many ancestries get darkvision or low light vision and it's strange. Basically I'd remove dark vision from a couple more races, replace it with something reasonable that makes lore sense and give darkvision to dragonborn.
