LCDs do not need to refresh the display unless content needs to be changed (they are essentially static displays). Hence, while a higher refresh rate improves flicker free performance on CRT and Plasmas and can make the display brighter with better motion performance, LCDs wont benefit from 120Hz or higher refresh rates.
However, as higher refresh rate LCDs typically have lower response time to refresh the screen, they may exhibit better motion resolution. Wish they could have accepted 120Hz input which can definitely improve motion performance. However, on a 50/60Hz input, higher refresh rate without motion interpolation may not improve PQ.