The self-publishing landscape has been transformed over the last 10 years or so. Before that self-publishing was equated with vanity publishing i.e.
I have written two books which will be published as Kindle & soft cover, print on demand.
A book must look right to sell. Even non-readers can tell at a glance that a book does not look right.
The advantages of self-publishing on Amazon kdp (kindle and/or softcover print on demand) include total control over the project and receiving 100% profits from the book.
I am in the process of learning how to publish books through Amazon KDP. This allows an author to self-publish books in Kindle and in softcover print on demand.