As an interviewer I essentially never place any merit into Uni. If you're talking about specifically during the interview, it's rare that an interviewer is going to care much where you went to school. A tech interview is generally all about how well you can solve problems they throw at you (and the process by which you do it).
That said, there's a lot of stuff that happens before the interviewer talk to you, and afterwards.
Before, you have to make it through to a recruiter amidst a pile of other resumes. I would guess that Uni rep can help there.
After, depending on the company, the people actually making a decision may place some weight on Uni rep. That'll depend a lot on the company.
If you're specifically asking in the context of software/computer science, it's a lot less relevant than in other industries.