How Can a Book Publishing Consultant Help Authors?

I’m considering hiring a book publishing consultant for my first manuscript, but I’m unsure what to expect. Can a consultant really guide authors through editing, formatting, and distribution effectively, or does it depend on the individual? How do you choose a consultant who understands both the creative and business sides of publishing? I’d love to hear from writers who have worked with a book publishing consultant what made the experience valuable and what pitfalls should beginners avoid?