The final line printed by hugo help is:

Use "hugo [command] --help" for more information about a command.

(hugo --help prints the same, BTW.)

Typing hugo help new (for example) works fine.

Typing hugo new --help also works. (That's natural, since hugo --help recommends it.)

The command hugo help is undocumented, in the sense that help isn't included in the list of Available Commands printed by hugo --help.

Generally speaking, new users can feel "lost in a thicket" of new syntax. To help promote Hugo to new users, IMO hugo help should be included as an Available Command.

Some of the discussion in this Cobra PR seems relevant.