It was perfectly logical for two reasons: 1) starting with the first of the weakest Numbers (Leviathan Dragon) alongside introducing Xyz Monsters as a whole would've made the latter group seem useless by comparison, especially with all of the more-miss-than-hit effects of Xyz Monsters before they became more practical
That also gives you something to do with the second ability, because flickering this over and over with 4 or more power makes it a removal powerhouse
It was already somewhat well positioned in the meta, particularly against Ruby/Sapphire, and now, with Sapphire/Steel getting hit the hardest with bannings, its far better positioned
This mechanic seems like an interesting and clever way of celebrating the game's most iconic instant and sorcery cards, something the first Strixhaven set did through its Mystical Archive bonus sheet
Just get some boots and a FireshriekerFireshrieker on him
I hope it helped as an introduction to all the ways we can play this amazing game