Actually computers can be much better sound sources than CD players. You can buy as expensive DAC for your computer as your budget ever allows (most expensive ones are crazy expensive, like several tens of thousands). DAC is a very important component in sound system, especially so in audiophile setups. (CD players have a DAC build-in, quality depends on the price tag of the CD player)If I wanted audiophile quality, I wouldn't be using my imac and Mp3s as the source.
The other, even more important reason why computers are better sound sources is that you have whole lot of individual songs in your computer but your CD player can take only one disc at a time with limited number of songs. With your computer you can create what not kinds of playlists, and they can be as long as you want, you can listen to one album at a time or you can mix all songs of one artist or genre together or do what ever comes to your mind.
And no, no serious audiophile touches MP3s. But luckily there are these so called lossless audio codecs. And with computers you aren't stuck to CD quality sound, which is 44,1KHz/16bit, but you can have some 96KHz/24bit or even some crazy high resolutions like 192KHz/24bit and beyond.
So computers are not only better sounding sources than CD players, but you can have your whole music library only few presses away. And you don't need to listen to music in front of your computer, you can send it to your living room too - or any room.