I'm a big fan of university for university's sake.
I don't pretend it is for everyone or that what I'm about to say is universally true, but the very fact of attending a university helps most people become more rounded citizens, even if they only take piss easy courses or (as in the UK) a single subject track for their entire time there.
Universities by their very nature draw a more diverse and wide ranging crowd than local primary and secondary schools. Someone who has spent time in tertiary education is going to have encountered people from a wider range of backgrounds, areas, races, religions, etc. The value of this sort of mixing is invaluable.
It also offers an environment for people to fuck up with relative safety. You can experiment and reinvent yourself away from your childhood home and family without the immediate pressures of rent, work and bills. Well, less of the pressure anyway.
As far as the debt goes, it's almost filling the role that mortgages did for past generations. Which is a bad thing.
It used to be that your mortgage was what locked you into an area, job and lifestyle. Once you have such payments to make each month you can't really afford to take chances on a new career or make major changes to your life without very careful consideration. These days buying houses is so often a pipedream, but student loans and other debt have inflated to fill a similar role. You can't afford to risk unemployment even if you are current underemployed, simply because the payments need to be made. This stops people taking the risks that you saw so much more of in the 80s and 90s.