Comment 1 for bug 673364

--help and --usage are automatically added to all bzr commands, this isn't something specific to 'bzr-service'

They are similar, but not identical (though they may be identical for this specific command).

Specifically:
  --usage
     Print out the option arguments
  --help
    Print out the option arguments and the documentation for how everything is used.

As an example
$ bzr st --usage | wc -l
43

$ bzr st --help | wc -l
92