Does Incessant Cacophony make Hexblast impossible to cast?

Hello!
As a casual player, I'm making a lich build about Chaos and Curses. So, in a really casual way I'm looking around the skill tree for chaos and curses keyword.

I found in the lich ascendancy the node "Incessant Cacophony: curse you inflict have infinite duration". It sounds cool and it looks like the top tier curses node, deep in the lich ascendancy.
But I read in the hexblast skill small text "Can only detonate Curses for which at least half duration has expired".

So...

Does the "ultimate" curses passive node make completely useless the highest level curse skill? Or am I missing something?