Actually IPS (In-plane Switching) is just one type of a Thin Film Transistor Liquid Crystal Display or TFT-LCD.
And you are absolutely correct, IGZO (Indium-Gallium-Zinc-Oxide) is a semiconducting material used for TFT-LCD backplane transistors. The other material usually used for these TFT-LCD backplane transistors is amorphous Silicon (aSi).
Compared to amorphous Silicon (aSi), IGZO backplane transistors have a lot higher electron mobility, so their conductivity is just as good at a much smaller size.
Conductivity depends on electron mobility and mass. Higher electron mobility means less mass is required for the same conductivity.
With its small size thin film transistors compared to aSi thin film transistors, IGZO is useful for high density displays. At high density aSi thin film transistors would start to block a significant amount of the backlight, requiring more power to the backlight to compensate. This increases exponentially as the pixel density increases.
Less backlight is needed with IGZO-TFT-LCDs to get the display to a certain brightness. So all-in-all for current TFT-LCDs like IPS monitors, IGZO mostly translates into some power savings.
There is no difference in image quality or accuracy between an aSi-TFT-LCD IPS display and an IGZO-TFT-LCD IPS display.