it's an interesting talking point but that's about it in most cases. If you can find a role where some domain knowledge is related to your PhD subject, or they need the skills a PhD requires (i.e: academic writing) then it'll be very valuable, but a PhD in most places wouldn't actually add much value in the day to day: most SWE work is nonacademic.

Thinking to my own experience, PhDs are pretty uncommon but of those I've worked with, some are brilliant, and some are terrible -- just like non-PhDs. I wouldn't consider a candidate with a PhD better than a non-PhD candidate, but then some people would love to hire someone with a PhD. I'd say on balance, it's a positive to have, but I would never recommend someone pursue a PhD as a route into a SWE role. A year of hobbyist programming experience is enough to get a SWE job.