Equip Calvin with this and Scavenging (0) + Schoffner's Catalogue and you are now unbeatable!
The fact that this is an Arcane slot and non-unique makes it possible to hold 2 at the same time. If you would lose one, you could easily recycle it before you lose the second. And no need to upgrade to Scavenging (2) for this because this card is Fast!
Schoffner's Catalogue finances it all so that you can make this cycle Dark Horse friendly, and what's best is that it is an Item so also comes back using Scavenging.
Backpack (2) will be your friend to then pull it out before you reach the amount of damages that would put you in the danger zone.
Now bring your Five of Pentacles + Moon Pendant and bring Mysterious Benefactress on a 9-9-9-9 statline journey without any fear of dying.
This card is also good in Lily Chen that wants to fill up her Arcane Slots to use her Dragon Pole and benefits from this being the only Fast Arcane Slot Filler available to her.