A copy of a spell is created on the stack, so it's not "cast." Abilities that trigger when a player casts a spell won't trigger
For those who want to crash through combat: Caesar, Legion's Emperor, Jetmir, Nexus of Revels, and Ghired, Conclave Exile are terrifying options
If more than one replacement effect tries to tell a spell with buyback where to go, the player who controls the spell chooses which replacement effect to apply first
Other than fairly vanilla dorks (Stone Throwing Devils and Tundra Wolves) Naturalize represents a the first colour shifted reprint of a core effect
Depending on the state of the battle, you can grab the best strategic option or simply your strongest Pokemon
It also isnt part of the Reserved List, so in the event that narrow stax pieces like this ever catch on, Wizards of the Coast would be in the clear to reprint it