I've referred people senior to me and been told by the recruiter that it was significant.

Because I can't be expected to know their work as well as they do I describe their peers' opinions (well-respected in the NOC) and the soft-skills they have like mentoring, etc.

"Even though I was only an SDET, Dave took the time to help me fully understand the math involved in the problem domain and how to efficiently model it. This allowed for a 60% increase in my deliverables and put the entire team a week ahead of schedule."

I'm incredibly fortunate then, as that has never been my experience. Working in infrastructure engineering, I've been referred by devs for most of my jobs and in each instance the referral has been a positive. I've also referred a number of devs despite not being one myself, who have also benefited.