Well, the only time i have considered it as an option for my HQ is when i am playing with grotesques.
archon with djinn blade, drugs, shadowfield, phantasm grenade launcher.
put a haemonculus with power weapon and liquifier, 4 grotesques (liquifier, aberation scissor hand if you go for vehicles as well), so you have furious charge allready, and bonus whatever the drugs will roll.
i also have a 3 man unit of wracks, so when i play firat, have them on foot together with the archon, so he steals their pain token for 3 in total in the grots unit, so they are fearless.
if you play second, consider having them in reserves.
i had good games with that list, but ofcourse is not the most competitive thing. i just sometimes get frastrated by dark light weapons and take the matter of destroying enemy vehicles in the grots's hands.
well, got in to much detail, but wanted to explain the built of the archon. apart from this specific role, i wouldn't choose the djinn blade over the agonizer, nor would i choose malys (since she misses the grenades, although she is nice to negate the ID on grots from force weapons)