I had a server I rented from a provider in a data center and I wanted to image (dd) the drive for archival before I decommissioned it from my infrastructure.

Normally, you can't really do that with the OS running and you would have to shut down and insert a live USB or something and temporarily boot from that. The server being a faraway rental the only option was to open a ticket so that they could enable an out-of-band management option like KVM or IPMI. Which would allow you to control a machine as if you had a physical monitor, keyboard and mouse in front of you. With that you can attach flash drives, shutdown, restart, see the POST/BIOS/UEFI screens etc remotely .

But, I didn't want to wait 6-8 hours for them to enable that so instead I put together a process that would "boot" me into another distro "installed" into a RAM disk (kinda like how live CD/USB works) from the currently installed and running OS without rebooting

From there I could unmount the boot disk and do what ever I wanted from there, I could have even wiped the disk entirely and installed a entirely different distro if I wanted