
This becomes a must pick for high draw seeker decks in Dunwich Legacy.
Slot pressure is usually only to dream enhancing serum, of which you only need one. Orphic Theory can essentially block everyone's favorite treachery, beyond the veil. This ends up being a very strong counter to that card, as you can proc Orphic Theory just before you meet the criteria for Beyond the Veil to trigger. It breathes life into high draw seeker decks, which used to have to spec into Versatile -> Deny Existence to run that campaign.
Outside of that, it has some pretty great uses still for most high draw seekers. A couple of treacheries that come to mind are Arctic Wind (an absolute bane to high draw seekers in EoTE) and the possessed treacheries in Carcosa.
Overall, definitely don't count it out. If you're in a campaign with "safe" treacheries Farsight still probably wins the slot, but at 1 exp it's a godsend for those bad ones.