[Harp-L] flat keys

[Lloyd Short <lloyd.arthur.short@xxxxxxxxx>]

what's the real motivation for getting a flat key harp. Assuming no other
instruments existed in the world, and acoustic harp only remained, why
should I choose Bb over A or Eb over D? is there a tone difference ? I know
I just gave examples of a key sharp, not flat, but you should get the point
of what I'm asking.