The main reason everything is going digital is that, once the signal is converted to digital form, it doesn't degrade, and it can then be readily stored as a series of digital words which can be duplicated indefinitely without errors. And once a signal is in digital form it is easy to do all types of digital operations on the signal, such as analysis, filtering, modifying, etc. some of which are difficult or impossible with the signal in analog form.
Analog signals can degrade from many factors: noise (thermal and interference), channel bandwidth limits, amplifier distortion, etc. They are also difficult to store, duplicate and reproduce without further degradation. One area that is still mainly analog is in the high frequency RF area such as microwave signals, where digital processing is not yet fast enough to be practical.