What is Shutter Angle and Do You Need to Use It?

If seems whenever there is a new feature people feel they have to use it. Well shutter angle is not that new it has been around since cine cameras were first invented, that's when it was all done on film. The shutter angle was relevant because unlike a still camera the shutter was a spinning disc, if it was a semi circle then have of the time it was spinning the film was exposed. This is 180 degree shutter angle but you could have other angles changing the exposure.
In today's digital cameras there is not spinning disc so why do we still use shutter angle?