I worked at a UARC in Maryland about 10 years ago, as an assistant (so take my words with a grain of salt). Among the PhDs we hired, there were some people who

I worked at a UARC in Maryland about 10 years ago, as an assistant (so take my words with a grain of salt). Among the PhDs we hired, there were some people who struggled in their job search because they did laborious research that didn't yield a lot of publications. Others were coming from industry (and then returned to industry research). My PI came to the center because he was denied tenure on the campus we were affiliated with. Our research projects had a heavy focus on application and mostly yielded technical reports, not publications. We had to write a lot of BS boilerplate about how our projects contributed to national security. I got some co-author credits and a few conference posters out of the experience, but it was hard to pretend that it was high-impact research. My read is that a UARC is a crossroads for academics who aren't doing great in their careers and are on the way out into private industry or defense jobs.