AUO: Compared to a-Si, IGZO allows better light transmittance. This could mean a brighter LCD with the same backlight or the same level of brightness and lower power consumption with a less powerful backlight.
Cramming more pixels used to mean having to cram more LEDs (or the same number but with brighter LEDs, or more efficient and more expensive optical films, etc.) into the backlight to maintain the same brightness levels, but with IGZO not so much. Folks, as well as governments, will want large 4K2K LCDs that sip power and that means TFTs of the future will be increasingly made with IGZO.