This cards ability is often associated with goblins too, so you can kind of picture everyone in the art turning into a goblin for like five seconds
A third possibility, and in my opinion the most likely, is something a lot of redditors are pointing at
These proxies are more than just play figures
Each is a set of two 60-card decks featuring cards specifically designed for new players and an instruction booklet that goes over the games basic rules and cadence of play
This concept applies directly to Lorcana, but Magic has had 30 years to solidify their color identities, and as such, subsequent set releases will likely alter Lorcanas ink identities in the years to come
From playing with the heroes such as Yuna, Wakka, and Auron, to even finding uses for the minor moments such as the traveling shopkeeper Oaka constantly asking you for money (though in MTG hes after your counters to exchange for drawing more cards)