My job involves many pockets of down time, and I read for pleasure and to reduce stress. I find that my work day goes by more smoothly when I have a good book to return to when I'm not interacting with patrons (also looks better on the job than going on my phone), and often someone will spark a conversation with me based on whatever book they see beside me, potentially leaving a more personal impression of my workplace on them, which I value. But I'm sure one could apply this to any hobby that would be appropriate for picking up and putting down at the workplace.

When I work on more hands-on jobs, similarly my day is considerably less stressful if I know I can at least read on the way to and from work, since I commute via train. Helps me get out of work-related tunnel vision.

I think any hobby that aids your mental wellbeing can positively impact your career, or any other aspect of your life. As others have stated, much depends on WHAT you're reading, how you're reading it, and what you're applying it to. A pretty loaded question, but this thread has been interesting to scroll through