Small details can be lost because bright backlighting causes blooming. Transparency is accurately captured. Works best for opaque objects. Can be used for transparent items, but the color image that will be masked has contribution of background color still in it. Very fast .
All images require the same amount of user effort.
Only file size affects the time required. But it usually takes several attempts to get the lighting just right for the contrast matte. Requires two photographs . Also requires two photographs. Once again, can be done by a chimp .