I'm really enjoying the game mode so far, and I really like the challenge of managing feat completions, data card selection, and stamina.
This might be a different reality in hard mode, but I'm finding I have a double incentive to let my energy refresh naturally: I don't use crystals and I recover a lot of stamina while I wait for my energy to fill back up. Because of this stamina has been a non-factor so far.
If we got bonus energy three times a day, and the event was only a week long instead of two weeks, it would allow players to play more battles quickly (engage with the game mode for more consecutive time) and make stamina more of a factor.