"How do I change my last commit message" is confusing

[aeciorc]

The difference between --ammend and --ammend -o is not clear here.

--amend without other options combines the currently staged changes with the last commit

To update the last message even if there are staged changes (...) then you can use the -o

Am I missing something or does the wording above makes it seem like the two commands do the same thing?