The same is true for permanent spells you control and nonland permanent cards you own that aren't on the battlefield
The advantage of it, though, is that green gives these decks access to Chord of Calling, which can result in an instant-speed win with the right set-up
From my experience, aggro decks dont perform all too well at a Commander table, but it looks like Animated Army has quite a bit of extra play to it that might turn that around
Three ETB art variants were released: Charizard (most valuable), Blastoise, and Venusaur
Winning during the opening turns is trivial, and youre packing extremely specific interaction to stop other common strategies trying to do the same thing
Zeriam's power comes from the fact that it is self-propagating