This is a good question and one I've recently wondered about, I found this article to be very informative once you ignore his complaints about 'cheap plastic photography lenses with no focus rings and variable apertures'. Lets assume we're talking about professional lenses here (L lenses etc), his points were
Cine lenses have more of a 'oiled' or damped focus/zoom feel which aids in not jarring the viewer with the fact that focus/zoom is changing. I agree, all my (many) L lenses are very snappy on focus and zoom which is helpful when quickly changing focus & zoom before shooting a photo but could be jarring if not compensated for when shooting video.
Cine lenses have more variable aperture adjustment ON the lens which he points out that even if your camera can adjust aperture while recording it can only do it in 1/2 to 1/3 steps which can be jarring for the viewer.
Cine lenses have gearing built in for follow focus (but you can add this w/varing degrees of succes with aftermarket modifications to photo lenses).
It looks like it comes down to photo lenses are optimized to help you quickly change settings before/between shots and cine lenses are optimized to prevent viewers from noticing changes you're making while recording.