This isn't bad, per se, and it has a worthwhile message of simply enjoying your own schtick with a decent plot twist at the end , but it takes too long to get to the point. I suppose it's best summed up with "good concept, poor execution."
Despite my low rating, I really did enjoy this book. The characters were all very entertaining, and the comedy banter especially was very on point. 029's art conveys the lighthearted spirit very well. If I could give a 3.5 on this website this book would fit comfortably in that spot. The thing is, the story is extremely disconnected. I love a good low/no stakes slice of life, but even those have pacing that takes you naturally from one bit to the next, whereas in Supernatural Battles each chapter just kinda does it's own thing by having a single main scene or encounter and playing with that until it's bored, then moving on to the next one. It made for an entertaining read, but left me feeling almost nothing when I reached the end, because the last chapter was just another, "Oh, I guess that happens next, huh?" kind of scenario. It didn't really feel like a conclusion.