The notes about filling detachment and obj. secured are ones I'll second.
I'll also note that, for me, some of the real value of buying Kabalites is getting access to a Dissie Raider. Yeah, the Blaster is great, but the Dissie spam is really powerful, and I get more Dissies with Kabs than I ever would with Trueborn.
Also, with the number of horde armies still in the meta, paying extra points for Blasters and losing out on poison shots is actually something you need to debate if it's worth it. My list has plenty of darklight, and I don't need to pay more to weaken my anti-infantry options.