Rhythm is an important feature of poetry, especially classical poetry. The Enlightenment of Rhythm has detailed descriptions and examples of flat and flat tones and rhythms. But with the popularity of vernacular Chinese and the rise of modern poetry, it is no longer necessary to pay attention to rhythm as in the past. In other words, modern poetry is free and casual.
But if you put more effort into the rhythm, you can make the poem easier to read and feel more neat.