Yeah, it probably was necessary. Thematically, it's supposed to be a nation of Vanir, not a nation of little black dwarves with Vanir slave-warriors to do the dirty work.
-Max
P.S. Also keep in mind that those 160 gp researchers can each forge an owl quill for 3 air gems (once the Svartalfs start passing around the Dwarven hammers) as well having access as skull mentors and lightless lanterns forged by Svartalfs. The actual effect might be that Helheim becomes reliant on gem income for research, which is not necessarily all that bad a thing, but it does take some time to kick-start (time which the face-hugging can purchase).