On the other hand, I think daggers have been made ~useless by this change..? Why use dagger instead of a shortsword/scimitar if you can just swap freely to a ranged weapon?

I think the only (BG3-relevant) class that might wield a dagger is the Trickery Cleric. Everyone else either gets at least one finesse martial weapon proficiency or would almost-exclusively use quarterstaffs/cantrips/ranged weapons.