One of the things I like about Clamp is that it is actually quite hard to use properly, to know when to use it to dig, when to use it for protection and when not to use it at all
While I think the whole "you have to wait for him" mechanic is a little goofy since he's only a 6/6 vanilla, drawing cards makes your Act of Treasons potentially cycle (or better in the case of the ones that steal a bunch of dudes!), which is an absurdly cool effect
Elsa, Snow Queen (D23 promo) The most expensive Lorcana Elsa card, by a long shot
Being able to cast spells from your graveyard gives you opportunities to recast powerful removal spells like Swords to Plowshares over and over again to keep your opponents off the board
Paying one mana to bypass an entire casting cost is why reanimation remains one of the most feared strategies in the game
Regardless, it should always be pretty valuable for collectors