UX writing is not marketing copy. Marketing seeks to persuade and attract attention; UX writing seeks to guide action, reduce cognitive load, and eliminate ambiguity.
Clear: Unambiguous vocabulary written in plain language. Eliminate internal company jargon and technical abstractions.
Concise: Scannable text stripped of filler words. Users do not read software; they scan it for triggers.
Useful: Every phrase must help the user accomplish their immediate task or recover from an impasse.