Heirloom of Hyperborea may look like a standard asset with draw a card when you do a specific action. However, it differs in one significant way: It does not exhaust.

When first printed there weren’t that many good spell cards, so the lack of exhaust didn’t really matter. Now there are many good spells so the limiting factor for normal Agnes is instead the lack of resources to be able to play them. Parallel Agnes can get around that limitation and is able to spam event spells, constantly drawing new cards to replace the cards just played.

There is a very good reason why all other similar cards exhaust and this is a relic from the time when they hadn’t realized that.