Original sin hexblast/comet

Hello, guys! Finally bought original sin today and its kinda...disappointing. How exactly it should work? If I compare hexblast dps, it doesn't change anything(I have archmage and few extra damage stats, none of them converted). For comet it converts cold(not lightjing) to chaos, but approx. same dps, so, I suppose, scaling from chaos damage doesn't work as expected.

What I miss at all? Are there any usage other then applying chaos related effects?