And once we start to concidering that "just one another choice" ... we might be easily surprised how many additional work we just created.
Where you see work, I see opportunity.
On the work side, let the "city of origin" tag default to zero, for both the player character (until he, she, or it establishes a point of origin through dialogue) and all NPCs for whom city of origin is not important. Then, set up a limited number of "gab" responses that any casual NPCs with cities of origin can use with the player character. Finally, for important NPCs, dialogue writers have the option of deciding for that character how important their home city is, how they feel about the PC's home city, what they have to say about it, and what the PC has to say about what they have to say about it. They don't need to, if it's not really relevant to the NPC, but if they do, all they really need is a "reaction" line.
Boom. The work drops from exponential to near-linear.
On the opportunity side, immersion counts. Right now, we have one and only one option if we want to declare a city of origin - but Faerun is a pretty big place, with lots of different cultures intermingling. Being able to declare a different home, and getting an occasional shout-out to that home (for good or for bad), rewards you for your backstory (or part of it), and can give a stronger sense of connection.
However, I don't think we'd be having this conversation at all if Larian hadn't given us the option to declare ourselves Baldurians in the first place. I, for one, would be perfectly happy with a blank sheet that I can write on myself, so long as it was truly blank. Not exactly a fan of being told repeatedly that my character is a parent in search of his or her child in a post-apocalyptic wasteland, for instance.
