It is not the best option. A program will never beat a good editor. The only thing I suggest is that a writer uses a program to help as they work or write. This helps make your book cleaner and causes less effort on the editor – making them happy and if done well enough, could cause your rates with the editor to stay lower or low. If you have too many issues, an editor may demand more.But if you just cannot afford an editor, then the best way is to use a program, and have you do a full read through, and have someone else (friend) do a full read through…and the more the merrier.
Moreover, the casual distinction between a (developmental) “editor” and a “copyeditor” can be a bit simplistic, particularly in a self-publication or even vanity-publishing context. A self-published author may barely have the budget to hire one editor, so that editor needs to be able and willing to blur the lines between developmental editing and copyediting. The editor must also be accustomed to working with authors of a variety of strengths and weaknesses, including many whose work would not, in fact, have been accepted by a commercial publishing house in its current form. I have come to take great satisfaction in taking a new or newish author by the hand and helping them find ways of making their work the best it can be. Of necessity, this must include line-by-line correction of grammar and style (often a surprisingly great amount of such correction), but can rarely be limited to that.
Of course, my c.v. does include traditionally published books, but in those cases, I was hired (yes, on a freelance basis, which you would not “count”) by the publisher rather than by the author. The reason my marketing to authors instead emphasizes my experience with self-published and even vanity press authors is because working with a publisher is different from working directly with an author, particularly with an author who has made a conscious choice not to be traditionally published. Some might even say that working within a publishing house provides less preparation for working with self-published authors than does working with other self-published authors. I, however, would not go so far as to say that, because I really do believe we can come to our profession by different paths, just as people can come to writing by different paths.
2. Copyeditors aren’t the last line of defense when it comes to a book’s mistakes. Formatting, which is done after an editor has done their job, can lead to unintended errors being introduced into the text. That’s why it’s important to hire proofreaders to comb through edited text *after* the book has been formatted for print or digital. Proofreaders are your last line of defense—but they’re human too.