Countering creatures is great, but countering non-creatures is usually good enough, and this doesnt require another blue card and doesnt cost an extra resource
Also, Valiant triggers off abilities, so this is a reliable way to have that happen every single turn
It also sees a fair amount of play in Commander due to its storm potential, but mono-green isnt the best shell for it because it lacks the rituals that other colors like red or black have access to
In the sequels, you can't recruit monsters as allies, but the Beastmaster job can let you control them for that unit's current turn
After youve gotten a good density, this land can be a tutor for Sword of Feast and Famine, Mycosynth Lattice, or even Blightsteel Colossus
One like Strixhaven Stadium that only makes colorless mana and has no relevant upside just isnt going to cut it