Answer: 1. It makes the sonnet more musical.
2. It aid memory for recitation along with meter and it gives predictable pleasure.
3. It also help to establish the forms.
Explanation: Rhyme is the pulse of of poetry, as it makes it more defeasible, it is also its echo which enhance the beauty of poetry. Poetry express meaning with beauty, styles and feelings using sound and figure of speech to make language to the highest level. Poetry require planning which is simply the rhymes.