The decks incredibly consistent, with playsets of Ancient Stirrings, Chromatic Star, and Chromatic Sphere drawing bundles of cards and mitigating the restrictions of colorless mana while land tutors like Expedition Map find missing pieces
Keep in mind that the foil Cat token is actually worth a bit of money itself, selling for $4.50 at Card Kingdom
All told, the sorcery speed of this card probably holds it back more than the potential for it to be dealt with and the consequential aversion to targetting EtB effect creatures with it
There are many ways in UW to pop off with this (tapping and untapping, for instance), but you dont really even need them to enjoy the value that Shorikai brings
Essentially, the spell must be from a different expansion than every permanent you control and card in your graveyard to get the Treasure token
Another way to earn free packs is by winning events and drafts