You must have spent a good many kobans on Finalmecia trying to win her girls or something during the sale. I actually used a good bit I had saved up, but even I don't have her max yet. There was no need to rush and level Finalmecia up after I won her last girl, Zoe, at about 350 wins.
I've won every PVP battle I've fought since the update, and still don't make but about 50k to 75k max for every 18 to 30 battles won. That's per day as I only PVP at night after work. I get more than that per hour from my Harem! I don't see how that can be counted as any significant source or income, or at least it isn't one for me, and probably for most who actually work and sleep 8 hours a night.