It might seem silly, but MTG players have been known to covet cards with desirable art
Are you dead certain that it should stay banned for the health of the format
Their use cases go up in graveyard or flicker decks, of course
But it's important to balance them
You can check out our guide to Magic: The Gathering Booster Pack types here, but the short version is that Collector Boosters are filled with alt art, foil treated and special variants of cards in any given set
In fact, the only mono-blue cards in all the average decks put together are Roil ElementalRoil Elemental, Meloku the Clouded MirrorMeloku the Clouded Mirror, Retreat to CoralhelmRetreat to Coralhelm, and two Gate-related cards, Guild SummitGuild Summit and Way of the ThiefWay of the Thief