I have never played it, but I could imagine a scoring mechanism that would make it interesting, and perhaps is implied by the rules:

The score value starts at 1. Every additional "check" multiplies the score value by 2 (so 2, 4, 8, 16...). The first player to say "checkmate" receives the score. Track your summed score between games; the player with the highest overall score at any given time is "winning."

Isn't the optimal strategy just to say "checkmate" immediately? That dominates anything else.

It only works if there are more than two players