The first is that WotC put a lot of support behind Arena to reach a broad audience, and part of that is more MTGA-exclusive content including consistent ranked matches, best-of-one and best-of-three events
And that creature can't be blocked
While gold cards may not be the most desirable or the most expensive (likely on account of them simply sharing art with the Full Art cards) this version of Mew is definitely an eye-catcher and remains a strong and worthy addition to Pokmon 151
It also has a backup plan in its -3 ability, where it takes down a big threat while staying in the 2-loyalty range
There's no immediate combos at play here, and you're not in the colors to blink, reanimate, or otherwise loop Gladiolus, but there are ~11 Gates in Gruul so that might work
Notice that this deck only has a few cards with ward