Training. Faster and easier than books, doesn’t require reading. Best way to gain skill that I’ve found.
Also, I’ve seen claims about batch-crafting, but I haven’t ever really messed with it much myself.
Other than that, “disposable meat shield” is about all they are really good at. If you can manage to keep them away from combat, then they can pulp corpses for you, but that’s a MIGHTY big if - in my experience, they don’t run away well, once engages, so they tend to treat every fight as a valiant last stand… soon enough, that’s a self-fulfilling prophecy.
Oh, they are also a decent source of money - trade things you don’t need for credit until you have all their credit. Yay. Then, when they die, you can get the stuff back.