......
Because of this, I like to have their complete system on a live DVD that they can boot from when they mess things up completely or if they have to borrow one of my loaner computers.
The other reason that pendrives are not my main choice is that I mostly use older computers and a lot of them will not boot from a pen drive.
Of course, those days are probably nearly gone anyway at least as far as KDE goes.
What I would love to see is a version of livecd that will store the host operating system on a first DVD or CD and then allow for inserting 2nd or 3rd disks containing virtual operating systems and/or data partitions such that any idiot could restore a large system using only the internal optical drive.
Those things are possible .... just not with really old machines ........ you cannot make a silk purse out of a sow's ear

You can use a floppy or CD to boot a USB drive ......and store what you want on it
You could, if there was sufficient memory, copy the LiveOS to ram and use a DVD-RW or USB drive for writeable storage
You could install the liveOS on a bootable rewritable DVD-RW and use the DVD for storage
The best of all is the USB drive - flash or HDD .... it is faster, holds more data than DVD and does not have the same possibility of mis-reads as optical media.
I have seen a much higher percentage of dead pendrives than bad DVDs.
Then you are, I suggest, in a very small minority based on the number of coasters most people seem to generate ...... and the susceptibility of the media to damage.
