For some the following may sound obvious, but I am pretty sure many users consider DR as an advanced parameter only useful for certain pplications. But the usefulness of a high dynamic range sensor, i.e. a sensor that allows a wide range of RAW exposure values still keeping a good SNR (visible noise), goes beyond facing high dynamic range scenes. Other contexts are possible:
1. To take pictures of high dynamic range scenes: this is the obvious. Where other cameras could need to shoot more than once, or sacrifice highlight/shadow detail, a high DR sensor can capture an entire scene in a single shot.
DR -> enhanced captured DR, easier photographic procedure.
2. Make exposure mistakes and still have a good quality image: in a high DR sensor the user can make strong underexposure mistakes and still be able to obtain a good image by lifting the shadows, while other cameras would ruin the image because of noise. This is not only of interest to novice users, action photography is prone to produce exposure errors.
DR -> compensate errors made by the photographer.
3. Prevent motion blur/lack of DOF: if we are in the limit to achieve enough shutter speed and/or DOF, a high DR sensor allows to expose less by reducing exposure time and/or aperture, with a higher guarantee to avoid trepidation or insufficient DOF thanks to being able to underexpose the RAW file and still recover a high quality image.
DR -> ensuring sharp images and extended DOF
4. Finally if we can rely on our sensor's ability to lift the shadows in conventional scenes, we could even afford the contrary approach to ETTR, i.e. to deliberately underexpose by default all our shots so that we can forget about optimum exposure. The high DR sensor will guarantee a good image while we can focus on other photographic aspects such as framing, composition, focus,...
DR -> focus in creative and technical aspects such as composition, perfect focus,...
