Rhymes in poetry create a dreamlike impression because the continuous musicality created by the clash of similar-sounding vowels gives off an aura of 'daydreaming' that the continuity of prose cannot accomplish as effectively.
And since the art made for the soul is precisely this means of expressing subjective thoughts, they are essentially concerned with ideas whose experience in the real world is not yet possible. Imagined experiences are pure dreams, so this art made for the soul essentially expresses a dream.
The musical tone of poetry harmonizes perfectly with the heart of this type of art (art made by an artist who seeks to express their intimacy). Any thematic expression (which is an expression of one's intimacy) is thus accentuated when it is expressed poetically. The weakness of poetry is not being able to construct itself through a narrative by generating less tonal disturbances than prose.
Ultimately, the last sentence nullifies the conclusion 'Any thematic expression is accentuated when expressed poetically' since many themes must first be properly built up tonally in order to be adequately communicated.
