There's def. inspiration involved, but we're also innovating on top. The current game mode is just the alpha version.
First game put me at 5 hp vs someone at 15, so that seems like an error?
In async battle mode, you're being matched up with a previous players lineup. The 15 health are irrelevant as your opponent doesn't really "exist", since you're trying to win 10/10 rounds. Your 5 health reduces by 1 health each loss.
That for example does not exist within Battlegrounds and personally, I'm enjoying the fast pace of that mode quite a bit.