Its core ability lets you blink one of your creatures (removing it from and then returning it to the battlefield) every single time you play a noncreature spell for extra enter the battlefield (ETB) triggers
Floating mana isnt something we see on cheap cards very often, and adding mana on casting spells has proven strong in the past (Birgi, God of Storytelling immediately jumps to mind)
This is a change from 2003s Pokemon Advanced set from Topps
Rakdos, Patron of Chaos was released in the Murders At Karlov Manor set and Rakdos, the Muscle came out in the Outlaws of Thunder Junction set
Plus, this kind of card rewards aggressive pilots looking to push early pressure and close out games fast
It was a new type of mana (something we don't make very often), required a new frame, and interacted with deck building in a new way