Being able to draw upwards of three cards in a turn at the expense of just three life means you will have plenty of opportunity to draw into some extra removal or combo pieces very quickly
(Someone wouldn't be silly enough to play Boundless Realms while Sire is out, would they?)
Even so, theres a set of lifegain cards in the deck that distract from the real goal, and there are some odd quirks that distract from the real goals
The best sets from the Sun & Moon era in the Pokemon TCG feature a collection of notable cards with iconic designs
With black not seeing much aggressive support in the MTGO Cubes I dont think well be seeing this in Vintage Cube, but its a very good fit for formats like the Arena Cubes
Disregarding that insane value, assuming youre in mono-green or have excellent fixing in Standard, it also has an activated ability to transform