Digital Video basically is better visual picture quality, which comes from higher pixel resolution. The more the pixels there are the smoother the picture will be.
Digital video is widely used today. There are digital camera recorders, digital television recorders, digital dvd recorders and pretty much most of the electronics today are digital.
In smaller visual device the resolution can not be noticed between analog and digital quality, but when the visual is larger, the pixels in analog video are clearly noticed, because they can only be stretched so far and the actual pixel blocks are no longer smooth. In digital video quality, the resolution is better because there are more pixels, and when enlarged they have the capability to be stretched. For example in digital cameras, 3-megapixel camera can develop photos up to 5X7, if you would like to get clear 8X10 photos, then a 5-megapixel camera is needed, and poster size photos a 8 to 10-megapixel camera is required. The pixels can stretch so much before the picture becomes blurry.
Also, for example an analog TV would have 680 megapixels, where as digital TV would have 1680 and up, which gives a clear and smooth picture in larger TV screens.