It resolves even if the spell is countered
So far, 21 Disney Lorcana starter decks have been released, each with their own play styles and ink combinations
Rather, it merges with the target creature and becomes one object represented by more than one card or token (see rule 730, Merging with Permanents)
While Aggron's rise from the ashes is impressive, it still has some ground to make up if it hopes to rise on this list
Once you reach the phase of the game where you can afford to do multiple things per turn, you need card draw to ensure you keep having things to do (Circle of Power, Fight On!, Travel the Overworld) or at least cards which can be used multiple times (flashback spells, Ring of the Lucii, Shambling Cieth, Relentless X-ATM092)
So, always build with the mindset of what would be most fun for you!