It's quite simple: convenience
Album?
Have to go through the trouble of driving to Best Buy. If you want to transfer it on your phone have to save it , then upload.
Digital cuts all that shyt out
Not to mention you can have a broken ass radio in your car, cd player or tape deck don't work but as long as you got a radio transmitter you can still listen to it. Can't do that with CDs
Most people including myself are listening to music through there phone.
I have livemixtapes, Spotify and iTunes music on my phone and can just plug an aux cord into it or if your car doesn't have that a radio transmitter and listen to whatever I want. Whenever I want. Can't do that with CDs.