It never gets card advantage for you but does afford you card quality, a discard outlet and a recursive threat
While Mill X cards like Wall of Lost Thoughts will churn through four cards for two mana, which isnt a terrible mana to mill ratio, without top deck knowledge theres no way of knowing what exactly youre putting in your graveyard
If you have more than one commander (because of a partner ability, for example), you choose one of your commanders when the ability resolves to determine how much damage the ability deals
Several fan-favorite Shinies will be included, and the cards will show off a sparkle animation when viewed
Moonmist became a little better in human decks thanks to the number of strong double-faced humans printed in recent sets, like Kefka, Court Mage
If you understand that, you stop forcing green into reactive roles and start building around what it actually does best