I’ve found I enjoy the hobbyist design as mental stimulation more than I do trying to earn a little extra money on the side.
I have a few sites that I improve periodically through design, and slowly but surely traffic has increased enough to make it worth continued development.
On the job I wear many hats, its nice to focus on just purely design when I’m at home in the evenings…or coding for fun, rather than trying to fit a square peg in a circular hole day after day.