Well, but what can skeletons and similar undead do?
Physical labor, for sure.
But they can`t use several technical devices - they aren`t proficient with technology, are they?
Dragonstar Factories won`t have a use for such a dumb worker.
On a new colony, they could be useful. Buildung up walls, fighting some enemies, that could all be done with undead.
A problem of Undead is, that you need somebody to control them, who has a magical training, and you need this guy always and all the time. When he is "lost", the undead might go mad, and are pretty dangerous...
But Robots can be programmed to never do anything wrong, even if they need some repairs from time to time...