Recording is the process of tracking each individual drum, instrument or vocal. Picking the best possible microphone to capture the sound as it should be captured. Deciding what to double or stack multiple times to get the desired sound. For sequenced music it is making sure that all tracks are separate, for instance a stereo track with a kick, snare and hi hat together is not ideal. The tracks need to be broken down so in the mix process I have control over individual sounds. I understand that the stereo mix of the entire track may sound good to you but once we add vocals everything changes. There needs to be frequency space for the vocals to fit into the mix. And what if after we record vocals I want to drop the snare for instance for a couple of bars to let the vocals stand out?  That can't happen unless everything is tracked out properly.  In a nutshell it is capturing the song to give me every option in the mix.