This answer mentions that CMOS sensors "cannot" use digital shutters where as CCD sensors can. Even if some models have the ability to, it is certainly typically for CMOS sensors to use mechanical shutters instead. Why might this be?
Preamble: I ask with a particular problem in mind. My mirror-less camera uses a CMOS sensor and has an electronic view finder. When the shutter is half pressed (exposure is calibrated, focus is set, the EVF frame-rate increases) the video image seems nigh on identical to the photo. The sensor is clearly able to accurately process a stream of light hitting the sensor into images without a mechanical shutter, so why is a digital shutter off the cards? As far as I can see the mechanical shutter wastes battery, obligately creates an audible noise, takes time to shut-open-shut-open, and makes the camera thicker and heavier.
This boils down to what is the advantage of a mechanical shutter in mirrorless CMOS cameras?