Too many children are tempted to use their phones to video bullying etc and post it - also alot of unwanted distractions - I think for secondary 6th forms and colleges it's fine but would agree with Iosoma that no to younger students.
We allows staff to access it, but disallow access to students. We have also developed an internal youtube like system that hosts videos that staff need to access. This seems to be the most flexible route, but can require some additional work!
I just leave it open for all, seems to work ok in our school