The contrast between the teal highlights and dark silhouette builds drama without excess
Some commonly played sideboard cards are: Splashes Splashing in DPS is relatively free, and it gives access to a lot of effects you wouldnt get with just two colors
205.4d: Any permanent with the supertype legendary is subject to the state-based action for legendary permanents, also called the legend rule (see rule 704.5j)
The downsides are real, though
you cannot Special Summon from the Extra Deck for the rest of this turn, except Xyz Monsters, also Special Summon 1 non-Warrior Gogogo monster from your hand, Deck, or GY, then, if this card is in Attack Position, change it to Defense Position
Once the set officially releases in a week or two and people start cracking boxes, prices are going to drop and drop a lot