Agree if I want the entire filesystem on the partition.
In the case where I was moving an installed Linux to a USB drive, I wanted to leave out certain parts of the filesystem – those directories like /proc and /dev … that are populated at boot time, and I also wanted to avoid any mounts,
so I used rsync because it has --exclude option.
Also I was copying to a smaller partition.
But I think that is a special case , copying a running linux system.
In general gparted will beat dd for safety and simplicity.
Right or wrong, I always create only one partition for each distro / (root partition). I don’t use swap partition (4 GB of RAM is plenty for my needs) and change the swappiness from the default 60 to 10 to use the swap file only if I have less than 10% of RAM free, which never happens in my case.
cat /proc/sys/vm/swappiness (to check the currently set number)
sysctl vm.swappiness=10 (as root to set the new number)
My root partitions are around 8 GB or smaller (Star Linux uses about 3 GB only and Debian about 4 GB). I always use an external storage or create a separate partition for that purpose, so only system files and apps are on the root partition. I am frequently experimenting with different distros, so I just format the existing root partition and install a new distro there. Simply copying a root partition using gparted to backup any distro is all that was necessary. In more complex scenarios gparted may not be the best tool.