It's clear via the reporting from IGN and the comments made by Holt and Deveny that the team at WotC has a great love for this franchise, which in part led to the choices of Final Fantasy VI and Final Fantasy X due to the places those games held in the team's hearts
Overall, Amethyst, Ruby, and Steel are more focused on attacking while Amber, Emerald, and Sapphire are more supportive, but each can be used to make interesting combinations and people can experiment with seeing what strategies work with their personal play style
While this card has an interesting ability, its undoubtedly its artwork that propels it to the top of the list of cards to chase in Shimmering Skies
Alternatively, you could use a card like Goldberry, River-Daughter to move one of your Finality counters around to protect the artifacts you need the most