Experience tells me there are definitely sonic advantages to be gained in digital replay, by removing the mechanical interface of a CD transport mechanism, and streaming the stored musical data instead via network devices.
Remember that all a CD is, is a carrier for data embedded onto it, and all we want is to retrieve that data and reproduce the music contained therein as accurately as possible. Due to advances now in technology, a plastic disc, or a CD player and its associated mechanics, is no longer needed to facilitate that process; in fact it's simply an unnecessary (and often detrimental) added complication.
However, as ever in audio, there is never a 'free lunch', and so introducing computers into the audio reproduction chain, such as is necessary in order to process said musical data, causes its own problems, and which need to be addressed, for genuine high-fidelity sound to be obtained.
Therefore, in order to hear the improvements a good streaming set up can provide over a CD player, as with anything else, the set up of such has to be right, otherwise it will be no better, or perhaps worse, than a CD player - and of course there are CD players and CD players.
In that respect, I've heard streaming systems, playing an identical album to a CD player sound worse than the CD player used, and vice versa, so nothing here is 'set in stone'.
However, all else being equal, including the DAC used (and I've heard this numerous times with my own ears), the best network devices/streaming systems *will* outperform even the best CDPs, simply because any CD player is ultimately governed by the limitations of its transport mechanism/mechancial interface and error-correction circuitry.
You will only discover that, however, if you have all the necessary 'bits' at your disposal, in order to make some meaningful comparisons, in your own system, so until then disbelieve/pooh-pooh it if you wish, but the reality will be obvious when, or if, you hear what I've described for yourself
Marco.