Usage in storing or transmitting
Progressive scan (also known as: P-Scan) is used for most cathode ray tube (CRT) computer monitors, all LCD computer monitors, and most HDTVs as the display resolutions are progressive by nature. (Other CRT-type displays, such as SDTVs, typically display interlaced video only)
Some TVs, and most video projectors have one or more progressive scan inputs. Before HDTV became common, some high end displays supported 480p (480 vertical lines or resolution with progressive scan.) This allowed these displays to be used with devices which output progressive scan like progressive scan DVD players and certain video game consoles. HDTVs support the progressively scanned resolutions of 480p and 720p. 1080p displays are available, but are usually more expensive than the comparable lower resolution HDTV models. Computer monitors can use even greater display resolutions.
Advantages of progressive scan
For explanations of why interlacing was originally used, see Interlace. For an in-depth explanation of the fundamentals and advantages/disadvantages of converting interlaced video to a progressive format, see Deinterlacing.
Requires much higher bandwidth transmission rates than interlaced video of the same display resolution. As such, progressive signals requires higher bandwidth mediums in order to work, such as component video, HDMI, and digital broadcasting.