Way too many races have darkvision as it is.
Only underdark races should have it.
Why the hell do surface elves get it? Why do half-orcs and half-eves get it?
This goes back to Tolkien who had Elves run around under the light of the stars, before the Sun and Moon were created.
Orcs were corrupted/debased Elves so there you go ...
As to DnD - there is confusing and inconsistent terminology.
IIRC in some DnD editions - and in various other fantasy RPGs - there was a distinction between:
- infravision, for underground races
and
- low light vision, for surface races
As to the OP - I think that Dragonborn are a stupid race, whose only place is as mooks in the Dragonlance setting.