I've not yet melted a DVD-RAM or data CD, nor have I had one become unreadable. Contents will be at most 8GB, most likely less than 5, and should be something you can copy to hard disk or a thumb drive. Data disks, with respect to copy protection by encryption, are not the same as video DVDs. Copy protection is usually at the wholedisk level, to prevent duplication, rather than preventing installation on a computer.
Expecting media replacement for a book supplied digitally, in the event of destruction by you, is like expecting the publisher to replace a paper book if you drop it in the water while reading in the tub, or leave it sitting out in the rain.
Helms no longer offers manuals on paper? I know most shops now keep them on the network server, but didn't know paper was no longer available.