Indira, you seem more tech savy than I when it comes to this stuff and I would not refute anything that you have posted thus far. It's just when it comes to most games that I own there has been a significant difference when I picked up my benq xl2420t monitor, especially while playing BF3. Hell, even my desktop runs smoother on my 120hz monitor vs the 60hz monitor that I run along side it (opening tabs, dragging them around etc). It's just when I tried FFXIV I could not notice anything but a slight difference in colour. I assumed it was because of the 60fps cap.
yeah, is alot nicer on a higher hz monitor, each company has its own term for there add in frame technology thats what you see when you when you play it take the 60 base and adds frames between each one then you have 120 and so on, its a blessing from them that way we dont need god like pc's to see our games/movies run at them refresh rates. it pertty much just blends the frames together.