I mean, it helped that Shem-ha was basically Fine. Plus, they needed some way to deal with Hibiki and Miku's feelings without a) directly addressing them ever, b) making it last all the way to the end of the season and c) making Miku relevant in said battle (though I mean they showed how that could have happened otherwise towards the end of the episode).
Plus they didn't exactly need to top the AXZ boss.
I think XV Episode 13 is the only time it felt like a musical without it being a humorous element (Zababa's Orbital Beat and Beef Stroganoff).
The animation in this episode was amazing but I think it did get a bit deranged when
I hope they fix that for the BD release.
By the way
✰✰There is love everywhere, I already know✰✰