For Indigo Zap and Sour Sweet, it is a hobby and a passion that fits their love of aggression and brawling. For Sunny Flare and Sugarcoat, it is unnecessary as it goes against their pursuit of being refined ladies, but they sometimes do fencing to improve their agility and mental skill. But as for Lemon Zest, she is wild, so she would enjoy brawling for any petty reason she can think of.