A PhD is a two-edged sword. On the one hand, employers immediately assume you are mature, intelligent, and highly-motivated. On the flip side, they are generally not willing to pay PhD salaries.
Potential employers do make immediate assumptions about an applicant who has a PhD on their CV for sure; however those assumptions are not always as positive as you suggest.
When I'd completed my PhD the only jobs for which I could even get an interview were junior developer positions, same as I'd have gotten if I'd just come straight from primary degree to job market. The PhD counted for nothing & was in fact a bit of a sticking point. Interviewers seemed to think that getting a PhD involves sitting on your ass wasting time & that you'd do the same on their dime if they hired you. Of course, that's Ireland for you -- go figure.
Not that I'm bitter or anything