1. READOUTThe global shutter sensor reads all the pixels at the same time. There is no progression from top to bottom to capture the image, unlike with rolling shutter sensors. Mechanical curtains are not needed anymore.
2. DISTORTION Rolling shutter artifacts become a thing of the past: no more distortion when panning quickly, or when a fast subject moves inside your frame. This is especially good for videographers.
3. BANDINGLikewise, banding when working under certain types of artificial light sources, such as LEDs, becomes a no-brainer. No more risks of darker lines visible in your footage.
4. FLASHA global shutter can sync flash at high speed without the need for HSS. The A9 III can work up to 1/80,000s, and at this point the only limitation could be the duration of your flash.
5. POWERGlobal shutters didn't arrive earlier because they needed more power, and the circuitry is more complex. Sony found a solution with the stacked sensor design, without sacrificing speed (120fps with RAW files).