As per the title, I was just looking through Daemon Hunter, and thought these items seemed particularly useful, especially given their cost/availability. Basically, pack a few of these, and its a fairly solid "get out of jail free" card (or scroll I guess). And late game, they're so piss cheap that a psyker is effectively unable to trigger perils, with the amount of abilities they have to help mitigate that risk.
Or am I not seeing that they somehow become useless late game?
Anyway, just seems like they remove a bit of the fear/uncertainty from the game. You know, really hurting the themes of DH. Now, for the Daemon Hunter style campaign, I certainly see them as being useful, but perhaps it should be more limited (say have it negate any perils effects that involve daemons).