Disney Lorcana always continues to reveal cards in the time leading up to set releases, so more should keep trickling in ahead of the August launch of Shimmering Skies , including the rest of the Legendaries and the elusive Disney Lorcana Enchanted cards
Like many other forms of reselling, this comes down to luck, attention to detail, and good negotiation
Magic design is trying to adhere to those characteristics set by set but sometimes a card is released that doesn't seem to work within our conceptions of the colours of MTG - such a phenomenon we'd call a colour pie break
It currently sees competitive play in Modern and Pioneer, and will likely remain a Commander staple for landfall decks indefinitely
To hop on that question you asked @Quuador, at least I found that out through Bulbapedia
Part of the reason for this card's missing market price is its rarity, but the other portion can be attributed to its condition, which can shift this card's value by hundreds, if not thousands of dollars