I understand where you are coming from, and you would think this is true, but having studied language for a long time, I’ve never found this to be true. I love poems and songs in my second language, but the problem is that all languages are too massive in their size for poems and songs to teach you much.
Once you reach a reasonable degree of fluency movies with no subtitles are far more helpful.
Yes, I totally agree. I love especially 'The Raven' written by Edgar Allan Poe, 'The Highwayman' by Alfred Noyes, 'Do not go gentle into that good night' by Dylan Thomas, 'The Lady of Shallott' by Alfred Tennyson and 'Childe Roland to The Dark Tower Came' by Robert Browning.
Here you have some beautiful musical/recited renditions of some of these masterpieces.