[Samba] samba-tool domain backup online && --configfile

[Joachim Lindenberg]

On https://wiki.samba.org/index.php/Back_up_and_Restoring_a_Samba_AD_DC#Online_DC_backup there is a comment “you may want to specify a --configfile option so that the correct smb.conf settings get included in the backup.“ 
Why does samba-tool not pick up the one it (or other parts of Samba) is compiled with automatically? Like `smbd -b | grep "CONFIGFILE" | sed -n -E 's/CONFIGFILE:(.*)/\1/p' | xargs` ?
Joachim