User blog comment:FairyRaven/Fairy Tail Chapter 471: Until the Battle is Done, Review and Commentary/@comment-26822192-20160202205043/@comment-7418318-20160203084154

Considering how Serena had eight different elements, taking him out with a physical attack is actually a safer way to kill him, since he can't eat that for sure. So not using a spell doesn't mean he wasn't serious... not by itself anyway.

I agree that he didn't seem at all serious when taking out Serena, but for different reasons than not using spells.