Tbh, i understand the argument (somewhat). The media is bound to a CD so normal use would be to just read from the CD. Digitizing it to a digital file is another step. An ebook is a digital file to begin with. You must actively break the law where you just need to forget the empty your trashbin with the digital ebook.

There is also this huge deal with for example Windows Licenses. You are not allowed to resell Windows Licenses you no longer need, except when they are printed on (for example) a Laptop to begin with, then you can sell the device with the Licence.

For the current law interpretation it is really important if the digital good is somewhat bound to a real object (CD or comes printed out) or if it just digital.