When staff are using their mobile phones to look up student information, it would be very handy to be able to click phone numbers to start calls, similar to email addresses.
Even if it wasn't a direct follow-through (a warning pop-up "Do you wish to call this number?", maybe) it would still be smoother than trying to copy and paste from the contact card.
If you use a directory, the phone numbers on the "show additional information" screen are clickable in mobile view. It would however be nice for this functionality to be available in more areas.