It's prolly for the visual. Doing it sparingly will help the readers ground in the world. So they have some general idea of toasting is like in that world. (could be otherworldly toast if the setting isn't based on real world).
Not sure if that contributes the plot, likely unrelated.
Love it! However the continuous battle, one after another could be a bit tired. It needs to be doing in conjunction with the narrative. Think of many tournaments will have certain glimpse of the backstory. So we understand the players better?
My first novel (6 LN books) has like 50 readers so it's not too bad haha. I still love that novel and plan to reread it again after so many reads. (yes, I read my own novels, I'm the biggest fan, actually)