Art-wise: Because it's Emilia turned into a Mermaid Ghost! And Merrows in fantasy arts are always interesting. And her staff is a Ceremonial Mirror Staff with Gusta symbol... Plus, the part of Wynnda's dragon staff is also featured there...
And those Gusta symbols in her eyes are outstanding.
This card currently is the only card that shows both Ritua stuff and Gusta stuff, and both are my favorite archetype.
Also, effect-wise...2 Level 4 monsters
If this card destroys a monster by battle, you can detach 1 Xyz Material from this card to return that monster to the Deck.
Not that great, but its decent to stop searchers or sending back card like Treeborn Frog to the deck.
And because she's also a Ritua monster, she has decent synergy with Emilia's effect to stop the trap cards.
Calling me Kaze or Kazemachi is as legit as calling me Eria.