Do we need line breaks?

[milo]

Yes.  And, when wondering why, think about what free verse would be without them.

Free verse without like breaks would be prose poetry. A very satisfying form.

From Hammes on prosody :

To this end, a poem is a communication that /makes
use of/ the line. It is not a prose communication or
incommunication hacked at random into short segments.
If you cut up a string of drool with scissors, it's not
only still drool, but mere proximity of the pieces causes
them to flow back together. And while this is extended
metaphor, it is not poetry.