It's a card that is both simple and subtle, flexible enough to pursue multiple goals and fit into varied sets of decks and scenarios.
As indicated in the previous comments, the response to this card is made up of three (almost) independent sentences. Assuming that by its response you discard a treachery card at some point, its resolution by "When revealed" will NOT be mandatory, because this card is not revealed but discarded with "resolved effect" option. This means that we can simply discard this treachery without any consequences otherwise (neither negative with the treachery effect, nor positive with the readying), to simply benefit from the +1 .
This event has three notable interests which can be combined :
1) Granting a willpower bonus to all characters (heroes or allies, unique or not) engaged in the quest, just before the quest resolution step.
2) Readying the questing characters to take advantage of their possible versatility (an action triggerable during this phase 3 or later, or good stats usable in combat).
3) Discarding many encounter cards that bother us.
For 2-cost, there are two conditions to be able to take full advantage of it :
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Treacheries must be manageable, obsolete or painless for our deck and our cards in play (which also depends a lot on the scenario, of course)
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We must be able to scry and manipulate the encounter deck. A few steps before playing A Desperate Path we can for example trigger Far-sighted, Interrogation, or Risk Some Light. Another interesting card to play before A Desperate Path is Shadow of the Past if some treachery without serious consequences sits at the top of the encounter discard pile.