I guess an issue is that the cut-scenes are all prerendered(and will like remain that way for the PS4), at 30fps. It would be jarring if the game is switching between framerates like that.
It's not as if this is a re-master of a 10 year old game where they don't have access to CGI models, ND just uses the super highest quality assets they already make use of inside the game and the game's own engine to create those.
So WEBM that shit and give us 60fps cut-scenes!
Also, there are games that do switch fps because of cut-scenes, while indeed distracting, it shouldn't be a reason to not go 60fps which you'd be subjected to 90% of the time.
edit: Even if ND does a 60fps with no slow-downs, give those poor souls who think 30fps is essential to being "cinematic", a 30 fps option with lots of motion blur. I'ven been converted to 60fps movies thanks to my LG set that does frame interpolation. This makes me a traitor to movie purists.