What is the purpose of having 3 different battlefields and how are they used in matches?

Ruling: In a best of 3 match, you must rotate through the 3 battlefields (you cannot pick a battlefield already used). In a best of 1 match, both players must randomly pick a battlefield from their deck of 3 battlefields.

Sequence:

• Best of 3: Rotate through all 3 battlefields, no repeats allowed
• Best of 1: Randomly select one battlefield from the 3 available

Nuances:

• Some players pick battlefields of their choice in best of 1 for playtesting purposes, but this is not the official rule