Jeez, the misinformation here is awful.
No, Cambridge care little for extracurriculars - it's good to have, but just hurling it into your PS without any reflection of what you gained from it will get you nowhere. Strong academics come first and foremost.
OP, with a UMS average that high, I am surprised that you weren't even offered an interview, given Cambridge's convention of interviewing the vast majority of applicants. Sadly, mistakes can occur, so requesting feedback may be a good idea.