2 xp card for a fast Old Book of Lore use/Eureka effect for each player, but you can't always control when it happens because it's a dilemma. That sounds expensive, but possibly justifiable.
But, you also get all of the weaknesses you don't choose back for free! And you remove all of the non-weakness cards (which you put in your deck, so you probably want them, with the possible exception of a few signature cards if you don't build your deck to use them) from the game instead of discarding. And the card is Survivor, which is the class who can recur things.
The deck-thinning means you probably don't want to recur it, so it's a single-use event for 2 xp, with drawbacks.