CDs and DVDs are digital media. There is no degradation of the content when you convert a fragile physical disk into a dumped ISO, and the dumped ISO can be stored on an arbitrarily large number of devices. Stuff like physical books or analog media (vinyl records, for example) are worth caring about physical degradation for, but a “physical copy” of a PC software disc is just a more fragile way to store the exact same ones and zeroes that can be stored on actually resilient media.