Consistency

Repetition is one kind of consistency.   A six-sigma production line, churning out identical widgets by the thousand.

Rhyme is another kind of consistency.  Similar, but different.  Assonance, consonance, alliteration.   Particularly pleasing variations within a coherent whole.

Both types of consistency are needed.  But they need to be in the right place.

On the whole, humans work better with rhyme than repetition.