Subsidy publishing has been around for years. Authors who could not or did not wish to use a traditional publisher would go there, pay for the publishing costs, and have their book printed.
Advantages
You will save time and frustration of rejections. It might take years to push your book through if you go the traditional route, submitting your work to publishers, waiting for their response, and gathering your collection of rejection letters. When and if your book is finally accepted, it will take another year, if not two, before it is at last printed and available in bookstores. For many authors, that alone is enough of a reason to consider self-publishing.
You will have full control over your work. No one will change your title (many traditional publishers do), no editor will tell you to add or remove 10,000 words, rewrite certain episodes or change certain parts of the plot. You will have the book cover done exactly the way you want it – a luxury most traditional publishers do not give to their authors.
You will have a chance as a writer. This is probably more important than anything else. If you have written a good book and have done a great job of publishing and promoting it, you have a chance to get noticed as a writer. If people like your book and start buying it, traditional publishers might become interested in it as well and offer you a contract.