As far as I can see, there's one simple reason why good two-color lands are kept at rare: it helps sell packs
Sazh's Chocobo and Traveling Chocobo put in a lot of work, especially with some old goodies like Mockingbird
The deck features a number of wrath effects to keep the board free and clear of threats from creature-heavy decks, as well as enchantments that can slow your opponent's attack
Collapse 7B, Sacrifice CARDNAME: Each opponent loses 7 life
The art treatments, foil technology, and rarity distribution are all tailored to appeal to long-term collectors and new collectors alike
In the end, playing MTG Arena on phones is a good experience, though given the complexity of the game itself no matter what platform itll be more difficult to follow whats happening with more complex card interactions than simpler competitive card games like Hearthstone