In the grand scheme of things, FPS is important but so is your refresh rate as these two are an important aspect to understand their relation to FPS. A person with 30fps vs a person with 200 fps, Will there be a difference? Yes but one should understand that a monitor with a 60hz refresh will only see 60 FPS with vsync enabled any FPS above this will see screen taring, moreover, although when moving in a forward motion the aspect of 60 vs 200 fps is generally easy to spot but really a person may not notice it, however if you move the screen from left to right you see why 60fps is a chunky cow compared to 200fps. With a 60hz monitor pushing 200 fps it would be a screen tearing mess and therefore you would, if buying a monitor and your capable of getting 200+fps in games then you will want a 200mhz monitor so as to be able to have vsync on (perfect picture). So in the end, high frame rates really look better going side to side when matching the monitors maximum refresh rate. If your struggling with getting 30 fps then a 60hz monitor with be fine the but the side to side motion will be horrible. So as a rule you would match your monitor max refresh to your average FPS in games. For example if your getting about 80 to 100fps in all your games a 120mhz monitor will be fine. Vsync is your friend. So good FPS is not just moving forward on your screen but side to side movement is also an important factor that plays into the overall quality of the FPS. I hope this provides a better understanding as to why FPS are important.
Cheers
PACO572