While it would be great if the email to a client could be more eloquent, it might not be worth the time. But other types of writing benefit from added eloquence.
Indeed, an eloquent brief is more persuasive. Yes, writing must first be clear, correct, and readable. And yes, the arguments themselves must be persuasive and supported by the law. But presentation matters.
Using rhetorical devises can convey your meaning in a more vivid and meaningful way. Using certain figures of speech can also motivate the decision maker to see the outcome your way. So, this essay will cover simile, metaphor, anaphora, antithesis, chiasmus, isocolon, metonymy, and synecdoche—figures of speech you can use to create a more clear, energetic, memorable, and striking written work. [excerpt}
Tenielle Fordyce-Ruff, Adding Eloquence to Your Legal Writing with Figures of Speech, 56(5) Advocate 48 (2013).