Since a lot of the droids haven't been implemented at this point (which I understand as development continues) I'm wondering what the usefulness are for the ones available versus hiring a npc to do the job.
There are no droids that function as a builder, nor are there pilot NPCs that function as astromech droids. Currently only NPCs can build or produce, and only droids can autopilot. The only current feature I can think of, that droids AND NPCs can do is cybernetic implants. Otherwise, some NPCs work, and some droids work independently.