they said that about paper every time it's been invented, but the problem with paper is it's inability to handle too little humidity (dry rot) too much humidity (mildew etc) and it's tempting nesting site for insects that routinely eat tree leaves. oh and it's bitrate per energy put into it is atrocious especially if you throw in modern hermetically sealed deoxygenated and humidity controlled environs. but it is easy to copy, any schooled child can copy letters from one piece of paper to another. but computers are even more awesome for data sharing and copying. even if laws against it exist. but i digress. having an optical backup is fine, there are times where optical is necessary, but it doesn't prevent accidental damage of discs or make sorting them easier. bitrot detection is an underserved market. raid has it, bluray doesn't and some filesystems actively have deduplication to reduce the number of copies left undeleted are few. anyways, the best way to check for bitrot is by scanning the md5sum on them with a script that runs automatically on the server that sends out the files to the offsite and if bitrot is detected it simply requests the data from the off site storage. before it is lost.