Ever hear that we live in a digital world, well there are many reasons why we have moved away from analog, in many fields. But analog holds some distinct advantages over digital, which can never be overcome due to the fundamental way digital is defined.
While at first we as a race start with analog systems, problems quickly arose which could not be avoided with analog; as such digital means were invented in order to streamline processes and remove errors which are fundamental to analog. While analog signals are continuous, vs. digital signals which operate in pulses, and at set values.
By operating only at set values digital allows for the removal of error and noise as it occurs, were as in analog any errors introduced cannot be removed. A prime example in the use of analog phones which typically have a lot of static interference. Another down fall of analog not being able to filter out noise is when the signal degrades over time, in order to amplify the signal the noise also gets amplified. However, by using digital any noise or errors introduced can be removed as the signal can be rounded to the nearest value which can be output. This allows for signal to be amplified while removing noise. Thus your cell phone has no static when talking with people, even when talking with people across the globe.