Yes, you're right. I chose 'Backup - user files' instead of 'Backup - all files' without seeing a difference between them at the time.
I've been using SD for a while and this is the first time I've made that mistake - tiredness after a long busy day, coupled with the distinction between those two options making less sense to your mind when tired.
Perhaps the text could be made clearer for times like that: 'Backup - volume' and 'Backup - home dir only' maybe?
Thanks for your trouble-shooting