It's usually not easy to pursue your hobbies as a career. Most hobbies are hobbies for a reason, and that reason is that they're more fun to do than your job. Often, people work years and years to ever financially get into a position where they can leave their day job in pursuit of their hobbies. However, sometimes you get a golden opportunity to switch careers that you can't pass up.
For Redditor u/the_anecdotist135, this didn't come in the form of a competitive job offer or even a concrete opportunity, but rather, a challenge. He was doing way more work than his job title required and not being fairly compensated for it. When his boss's incompetent nephew struggled to create a website, it allowed OP to flex the UX skills that he's developed outside of work. When his other work started piling up, his boss said something that gave him the perfect out from this mismanaged company.