Musicals are, by nature, theatrical, meaning poetic, meaning having to move the audience's imagination and create a suspension of disbelief, by which I mean there's no fourth wall. ↗
One difference between poetry and lyrics is that lyrics sort of fade into the background. They fade on the page and live on the stage when set to music. ↗
Bright star, would I were steadfast as thou art--
Not in lone splendour hung aloft the night
And watching, with eternal lids apart,
Like nature's patient, sleepless Eremite. ↗