I think that these questions are really important (and really hard) to answer, because of the difference in context between the web and the ivory tower.
In my experience one of the reasons why web people are often suspect of university people is because of the elitist attitudes that are often so foregrounded in traditional higher ed. Several P2PU staff and volunteers, past and present have articulated this over the years.
And yet, for many people, it is access to this elite (and I'm talking intellectual here, not financial, that's a different kettle of snobs) that is the major drawcard of the university.
For many people, it's not about vocational training, it's about entering a universe where learning has a long and rich history and where, over time, you are able to prove your intellectual worth and join your peers.
It's this peer acceptance that is the dovetail with what P2PU does.