What should you look for when hiring copywriters?

I’ve been trying to understand what really makes copywriters effective because there are so many different styles and approaches out there. Some focus more on storytelling, while others are very sales-driven, so it gets confusing to know what actually works best for different projects. From your experience, what should people prioritize when choosing copy writing support—creativity, marketing understanding, or industry experience? I’d really appreciate hearing honest opinions or real experiences from people who have worked with copywriters before.