I don't think he meant to have groups in general.
I think he meant to have *pre-defined default* user groups! So, that the most important permissions are already set up.
I don't know if that makes sense in DokuWiki, though. That also had to include a set of pre-defined default namespaces ...!?? Which doesn't make any sense at all ...
To put them up for the most general use would only mean having this default ACL:
* @admins 16
* @moderators 8
* @editors 4
* @guests 2
* @ALL 1
But most users wouldn't need this kind of ACL anyway, would they?
I'm not sure if this would be of any help or would only confuse things more!?