Their excellent shuffle feel enhances gameplay, making each game smooth and enjoyable
That would be because of mana burn
Add in Cheshire Cat, Not All There's and Kuzco, Temperamental Emperor's mutually assured destruction, Flynn Rider, Charming Rogue forcing you to discard (just one card), and Mother Gothel, Selfish Manipulator's ability to stop opponents questing, and Emerald decks will quickly become the most annoying to play against
This makes Shadowspear a great tool to slot into equipment packages, Trinket Mages bag of tricks, or simply as a silver bullet to deal with specific metagames
The new decks for Archazia's Island definitely feel like they're based on using glimmer team-ups (a trend that's been in Lorcana for a while), which might make customizing the deck a challenge