As someone who is not into musical episodes (nothing against musicals, just it's not my thing, if I wanted to watch a musical I'd watch... a musical?), it wasn't too painful to watch.
The Klingon segment made me howl with laughter though, and although musical episodes aren't my bag, I love how free this season has been in terms of exploring new ideas in each episode.
I enjoyed the episode. I liked that it wasn't just "a musical episode" but they acknowledged that it was unusual and expressed concern about it. They didn't pretend that everyone singing was normal like in a typical musical.
Yeah, they found a sciencey way to explain it that imo was satisfying enough. It's nice to have fun episodes so it's not all grim and serious, knowing what's probably waiting for Pike! Also a nice opportunity for some of the cast to show off their other talents, Christina Chong has an incredible voice.