Here’s some context to why my suggestion can be important:
I use my Pi as a pihole with the DHCP server enabled. Without my Pi running pihole no devices can contact uncached servers. I recently bought an Aragon One case which allows me to utilize an M.2 SATA SSD. So, I burned DietPi to my SSD, took out my SD card, proceeded to turn on my Pi, and type dietpi-backup, only to be met with a demand to update my packages and to download rsync. I couldn’t do that, because my Pi wasn’t running the DNS over DHCP yet.
I understand that I could skip the packages by changing the dietpi-backup command, but the fact that I have to download rsync makes restoring a backup impossible. I understand DietPi is meant to be as small as possible, but I believe rsync, and overall being able to restore a backup without internet, should at least be a minimum for fresh installs.