The reason it's so good in a Pikachu & Zekrom-GX deck is that it runs a lot of Pokemon that have very high Retreat Costs
That said, it's been kicking about the meta for a long time now and is still an absolute powerhouse - a fan favorite for a reason, and still more popular than other Dragapult builds - thanks to Charizard's dark typing making it a good matchup versus Gardevoir
It becomes especially potent alongside magecraft payoffs like Archmage Emeritus or Storm-Kiln Artist, which let you fully exploit the copied spells before finishing the turn with Grapeshot or a similar payoff
Aether Channeler, Sea Gate Oracle, Watcher of Tomorrow, Couldblazer, Augur of Bolas, and many more not only draw you extra cards, but in many cases let you take your pick of cards from the top of your deck
This is true even if that noncreature permanent became a creature the same turn it entered the battlefield