I just use CCC because I don't really care about old files I've personally chose to delete, don't want that taking up extra space on a HDD. I don't really need old music albums or duplicate photos archived that I have canned.
Also I do the CCC clone about once month so I've got about a months worth of stuff backed up any way in the event I delete something accidentally, which has never happened to me.
Both humans and programs can do screwy things. Humans are probably worse... but both happen.
I was once creating a "temp folder" of all my vacation photos for a project. I went into my pictures (filed by year) and "
copied" them over to the temp folder. Low and behold... by accident (or fumble fingers)... I "
moved" one by mistake. Of course... once the project was over, I deleted the "temp folder".
Two years later... I noticed that a full years worth of vacation photos were missing. No problem... I restored from backup.
Cloning would not have worked. Saving space on a backup drive is immaterial... storage is "free".
I consider myself as disciplined as anyone... we all make mistakes at some point in our lives.
YMMV.
/Jim