In the afterword of volume 1, Nishi writes that one day they suddenly felt like doing a manga about fighting games in Yuri-Hime, so phoned up and that led to the serialization. In vol 2, they answer the common question of why they thought to do it in YH. Apparently Nishi conceived of it as becoming very yuri if it reached the end. Trouble was the characters were all so absorbed with fighting games their relationships only change very slowly (so it's basically that thing of characters writing themselves). Nishi would have wanted to be able to write the story longer, even as far as a Vegas arc, but is surprised (and thankful) YH gave as much freedom as the manga had.