(in my opinion) A line break is a line break and punctuation is punctuation. Punctuation can be used to change the pace of a poem in ways line breaks can't.. and if a writer knows what they're doing, it can add a lot to it. Here's a good example...
What the Angels Left
by Marie Howe
At first, the scissors seemed perfectly harmless.
They lay on the kitchen table in the blue light.
Then I began to notice them all over the house,
at night in the pantry, or filling up bowls in the cellar
where there should have been apples. They appeared under rugs,
lumpy places where one would usually settle before the fire,
or suddenly shining in the sink at the bottom of soupy water.
Once, I found a pair in the garden, stuck in turned dirt
among the new bulbs, and one night, under my pillow,
I felt something like a cool long tooth and pulled them out
to lie next to me in the dark. Soon after that I began
to collect them, filling boxes, old shopping bags,
every suitcase I owned. I grew slightly uncomfortable
when company came. What if someone noticed them
when looking for forks or replacing dried dishes? I longed
to throw them out, but how could I get rid of something
that felt oddly like grace? It occurred to me finally
that I was meant to use them, and I resisted a growing compulsion
to cut my hair, although in moments of great distraction,
I thought it was my eyes they wanted, or my soft belly
—exhausted, in winter, I laid them out on the lawn.
The snow fell quite as usual, without any apparent hesitation
or discomfort. In spring, as expected, they were gone.
In their place, a slight metallic smell, and the dear muddy earth.