You don't really ever need >60Hz for editing though. You're working with 60fps, at most, but even more likely 30fps or 24fps.
I'm not much into video editing, but is it not useful that 120 hz is a multiple of 24, while 60 hz is not?
Remember all those 120hz and 240hz plasma TVs back in the day that couldn't take any >60hz input signal? Yeah that wasn't just pointless marketing. It was so they could show 24fps and 48fps video content smoothly, without 3:2 pulldown artifacts.
If you're working in a professional video studio, chances are you're probably going to encounter 24fps video. So yeah, still matters beyond gaming.