Only take for a deck that has a superb effect.
Akachi Onyele and Father Mateo have super powerful effects so they are obvious benefactors. Father Mateo especially likes this since he has a choice of benefits in addition to an "Automatic success" result.
An incredible trump card to play against a key opponent, a game-stopping treachery like Locked Door or to gain tempo during crunch-time. This card is as varied as the important tests that may come up. In single player try to hold onto this for those tests that you just aren't geared for (Aforementioned Locked Door is a good example of something that just screws over a . In multiplayer the card also gains a new niche as a way to net easy, no-risk kills on enemies engaged with your friends.
Don't forget that you can boost a buddy, characters like "Skids" O'Toole, Finn Edwards, Silas Marsh or Zoey Samaras all get massive benefits, some of which really kick off with foreknowledge (Like Zoey's damage buff, which is incredibly powerful when you can plan and account for it, all of a sudden she can one-shot a major threat.).