It's a matter of habit more than an absolute technical requirement.
Quoting the useradd manpage:
useradd is a low level utility for adding users. On Debian,
administrators should usually use adduser(8) instead.
The default SSH configuration is Debian 12 is as follows:
#PermitRootLogin prohibit-password
#PermitEmptyPasswords no
(The default values are commented out, ready to be tweaked by local
admins.)
It's pretty standard to have 127.0.0.1 match localhost while the actual
machine's name (FQDN and hostname) matches 127.0.1.1 instead.
We would be happy to be told if something similar exists for IPv6!
