Theres a few good reasons for that
Most of your characters have good stats for banishing their rivals in challenges, and if they don't there are easy ways to pump them up, either with a song, or as the side effect of a song
These full-card art secret rares go above the standard numbering and show a unique rainbow hexagon symbol on the bottom to further distinguish them
Each ink is named after a precious element, such as Amber, Amethyst, Emerald, Ruby, Sapphire, and Steel, and any combination of two of these is a viable deck for the standard game
the magnetic closure protects from dust and accidental openings
Restoring the Crown This Amethyst and Steel deck is filled with new keywords and mechanics from the Archazia's Island set