No. If you are a good writer, you might find that you can put together a perfectly usable CV by yourself.
This is often also the case when applying for entry-level positions or roles within smaller companies.
However, many people find that using a professional CV writing service gives them one less thing to worry about when it comes to job hunting. They are able to hand over their CV to someone who knows exactly how to help them stand out from the crowd; there are no worries about coming across as too bigheaded or not knowing which sections to put where.
Even if you have already written your CV, it can be a good idea to work with a professional service to review it and make sure it is the best it can possibly be.