I have an old Grundig CD 7500 player equivalent but better than Philips Cd303, when I listen to a cd it is really exciting what I hear compared to modern cd and dac players.
So my answer is keep the cd
Yeah, keep your CDs. They are your priceless collections. However, the aluminum layer in the CD can corrode away over time (disc rot). You need to check the condition of them from time to time. ITs best to keep a soft copy of the disc as backup just in case (just save them up as WAV or ISO files). If such a thing did happen, as least you can still burn a new one. ITs better than losing them (not all disc are replaceable as runs may be limited).