The person who writes clearly lets the reader spend energy on the issue itself.

Every unclear sentence transfers work to whoever reads it. They have to reconstruct what you meant before they can think about whether they agree, and that reconstruction uses up exactly the attention you wanted for the substance. Clarity is not a matter of style. It is a decision about who does the effort.

Before you send anything of consequence, read it once as the recipient rather than the sender. Cut what is decorative, say what you want, put the ask near the top. The compliment you are paying someone is that you did the hard part before it reached them.