Bear with me here, because this is going to get weird and as we all know "as if" invites all sorts of weird interactions (looking at you Luke) so I may get some things wrong here. This is simply a list of weird points I've noticed while looking at this card.
You can also save on a hand slot with Enchanted Bow if you feel like it.
As I understand it, "Seal ( )" isn't an ability but an additional cost to playing the card, so no cheating Seal of the Seventh Sign. But if you wanted to run them together, I THINK since True Magick says you MAY resolve the abilities by revealing them you don't really have to reveal the Seal you can just ignore the forced effect while it's in your hand, but I think you COULD if you wanted to? Dunno.
"Seal ( )" might not be an ability, but Shards of the Void really doesn't care since it also has "seal" in the ability. "As if" so... You seal the 0 on True Magick? Then activating it again you can release the 0? Oh, and if that works the way I described, couldn't you just also use True Magick as Shield of Faith? Not sure if that would discard True Magick or not.
This is getting weird, I'd better stop while I've still got 1 sanity left.
To me True Magick means efficiency, you don't need to play a spell for a 1 or 2 odd uses only to toss it away. You can keep a Shrivelling in your back pocket to pick off 1-2 health enemies all game, then actually play it before the final boss fight. It's a bit of a flavor fail that Dexter Drake doesn't mind tossing his spells around and would like this card a lot less than some other Mystics, especially ones with 5 free XP at the start.