I know none of these are amazing, just wondering if there are niche use cases for Aeonic staff where it might come in handy. I've seen some people put together some crazy Occult Acumen builds and gain TP like mad, not sure what to actually do with that though. Cataclysm builds maybe? IDK!
Its possible to really get a pretty amazing Occult set while still using your typical nuking staff to avoid loss of at least the token TP you already had if your build includes the ice cream cone, but yes technically you can get 1k in one T6 nuke with Khatvanga. Still not personally sure if its worth swapping to (I still don't even owning the staff), but probably depends on playstyle.
In terms Cataclysm/Earth Crusher cleaving- for raw damage there are better options but for most it would probably be the best choice for 1k TP spamming of the WS.
I wouldn't suggest to anyone to build a Khatvanga for legitimate reasons, but for the niche purposes you bring up it definitely has value. My only question has always been is the increased performance in those moments worth swapping weapons.