That's decided for you, and you won't know who you have until you bust open the box
Then again, Alchemy is a more fluid format of near-constant change than Standard, so it may not have been deemed "wasteful" enough by WoTC
And thus, Emerald Charm was a handy solution to any global enchantments (for you younglings, those enchantments which don't enchant anything in particular, such as Form of the Dragon or Worship), a way to bring flyers down to earth, and a second use of a utility creature, all wrapped into one neat little charm
...which lost in the first round of a tournament to a 14 year old running a combo deck with 40 land
Even if those two things are foolproof safeguardssomething I doubtpeople would have a hard time believing that if their collections all go to zero
Also as its name implies, Phantasmal Flames will have a special focus on Fire- and Darkness-type Pokmon