Since The Weekend Writer is a series for new writers, I'll send those readers over to the IndieReCon site to study up on hybrid writers. Hybrid writers, like my car that runs on both gas and electricity, operate two ways. They publish both traditionally and on their own.
Notice that agent Lara Perkins says that among the benefits of being a hybrid author is "hybrid authors often enjoy greater creative
control over self-published titles and over the scope of their career since
they have more control over what to publish, when, and how." An example? I'm familiar with a situation in which a traditionally published children's author is interested in pursuing publication for an adult work. (Hmm. Another type of hybrid?) Her agent and publisher are discouraging her, wanting her to be firmly branded as a children's author first. The writer is concerned about striking while the iron is hot (she's done well with her first book). Also, branding could be a two-edged sword. The adult publishing world may not be interested in her once she's been branded as not one of them. There's definitely an issue there about who is in control.
Notice that Perkins also writes about the challenges for hybrids. They are essentially "running a small business." It is "a tremendous amount of work." And speaking from experience, I can tell you that while you're doing the tremendous amount of work of running the business, you have trouble finding time to do more writing. For all the control that traditional publishers get over writers, they also take over a lot of the nonwriting burden of publishing.
Understand the pros and cons of both types of publishing.