The Tempo Twobert is designed to be evocative of low to the ground Legacy and Modern constructed decks, with efficient cards and creature combat being central to the gameplay. For a more in-depth look check out my writeup from the original design in 2021:

https://articles.starcitygames.com/magic-the-gathering/select/introducing-the-tempo-twobert/

The cards in the "maybeboard" constitute a Bonus Sheet to be drafted after the main Cube where each player will draft three additional cards with the goal being to make decks function a little more consistently. You can read more on this concept here:

https://articles.starcitygames.com/magic-the-gathering/how-bonus-sheets-play-in-my-twobert-magic-cubes/