To be clear, you can't cast both of this card's sides out of the command zone at the same time
On the first turn, you wont have anything to untap, but for the rest of the game, youll untap your lands so you can use them again, and your creatures so that they can attack again or be ready to block
However, since increasing deck size hampers your ability to actually find your key cards, it seems that it's only worth it for one-card combo kills and you should play lots of tutoring and filtering cards so you can find them faster
Players rushed to pick up their foil playsets
Summon: Valigarmanda is a great creature to bring back with Terra, so long as there are some strong Instants and Sorceries in graveyards you can replay
Although I think the pre- Bloomburrow rabbits are still the best options for commanders, that doesnt mean the new ones are bad