Capcom develops their games the stupid way and ties all sorts of stuff in their game engine to the framerate, mainly because they develop for consoles primarily and assume their games will run on standardized hardware at whatever framerate they will lock the game at. Capcom is getting desperate for money these days, so now they're releasing more of their games on PC, and these development decisions are now coming back to bite them.
Capcom has said they will give you the option to turn the framerate cap off, but they can't guarantee that you won't break the physics engine in the process or something, kind of like what happens when you disable Vsync in Skyrim. Since Dead Rising 3 is going to be a quick and dirty port, don't expect them to try to fix it, especially if it's a situation where they would need to rewrite the game engine in order to remove the cap without bugs.
The difference between 30 and 60 FPS mostly comes down to smoothness of the gameplay, particularly if you are using mouse and keyboard as your controls. 30 FPS can seem quite sluggish if you are used to being able to get 60FPS in most other titles. Basically, the game will feel a lot more responsive with at 60FPS compared to 30FPS. Console gamers might not notice or care about the difference as much, as gamepad controls aren't as sensitive as mouse and keyboard, and most console games made in the last 5 or 6 years have all been locked to 30FPS due to the aging console hardware not being able to deliver any more than that.
On paper, your rig should be able to deliver 60 FPS with the framerate cap off, though that's assuming the port doesn't have massive optimization issues.