I'd have to say the opposite is true. The boss battles will give less cash and XP than a normal battle, use up twice the battle points, and do nothing for you in the tower of fame. Eventually you will get to a point where they won't even give XP. The drop rate is so low as to be negligible. I think they do bump that up a bit for the holiday as most my drops came at that time. I've had six drops in three months playing daily. I had three of those near Christmas including two holiday drops available, and one yesterday. After three months, I have under a third of those available drops, many of which are no longer there. I now have all normal characters from the Dark Lord, one from the ninja spy, and none from the other three bosses. It took me three days of battles to get a quest item to move along and received no girl drops. I've made the decision not to even try for the holiday drops, as they are essentially the same girl. I think it would be weird to have say Christmas Arcana or Halloween Kimmie and not have the original.