Skipping this step is desirable because conversion to analog usually adds additional noise and is more susceptible to interference and sound degradation due to poor quality audio cables, etc. Conversion to analog also limits the resulting sound quality to being only as good as the DAC in the source or the ADC in the recorder. The end result of analog copying is a copy that doesn't sound exactly the same as the original. Some people can hear a distinct improvement in digital recording over an analog recording. Some people can't tell the difference at all.
Some people prefer one or the other.
Objectively, a digital recording is more accurate and should sound better. However, subjectively, an analog recording could sound better. It really depends on who is doing the listening. This digital source must also have a Digital Audio Output . Without a Digital Audio Output, you can only do an analog recording.