With analog signals, the voltage varies with the signal.
Analog signals are more prone to interference and noise. Although it's a lesser more obscure set of problems with digital signals.
With digital signals, just numbers are sent to represent the signal.
Ultimately, if you press a CD, the CD contains digital information. So starting with digital early in the recording chain tends to reduce the number of conversions from audible source to target (CD).
Analog is different to digital - and there are good reasons to use either.
My Roland synth modules, Pod XT Pro, Focusrite mic preamp, and Lexicon reverb unit all offer digital ins and outs. I use a Roland Digital mixer (M1000) to blend these. The audio signal is converted to numbers early in the chain and stays that way until the recording is made.