Nubian archers?

As Egypt, what is the advantage of Nubian archers over Desert archers? They have the same data from honga's site for attack:

Desert Archers:
7, 1, composite_arrow, 160, 30, missile, missile_mechanical, piercing, none, 25, 1, no

Nubian Archers:
7, 1, composite_arrow, 160, 30, missile, missile_mechanical, piercing, none, 25, 1, no

I don't really care about secondary weapon since I've probably lost if my archers are in melee. Nubian archers don't get the "Hardy" tag or desert bonus either. Its a bit of an expensive upgrade to pursue at all my castles to make them my standard archer...

They are better in non desert environments.

In what way are they better? I've got to justify those upgrade costs =) Is accuracy quantified in any way?

More defense and melee attack. Its all in the EDU file.