I believe self-published projects are the most important thing a freelance illustrator can be doing! If you're not working, they're a great way to add to a portfolio and build your brand. If you are working, they're a great way to have complete creative control over something and to take a break from client work.
Self published projects are also a great way to take a peek behind the curtain and learn the logistics of taking a project from start to finish and try on a bunch of hats. You get to be the Art Director, the Graphic Designer, the Supply Chain Manager, Marketer and more! Having that experience has definitely improved my workflow with clients, whether that's setting up illustrations for easy editing later or by working in a way that makes files easy to set up to market on social media.
Plus! There's honestly nothing cooler than holding a finished project in your hands that you've made literally every decision about. Books are fun! Cards are fun! Merch is fun! I hope you enjoy taking a peek behind the curtain on some of my favorite projects.