rsync function in fish that strips trailing slashes from arguments

safe-rsync.fish

# rsync, like BSD cp, interprets trailing slashes as "copy the contents of this
# directory".  But this interacts very badly with fish, which, unlike zsh, always
# adds a trailing slash when you complete a directory.  This rsync function
# fixes this behavior by stripping all trailing slashes.  You can still copy the
# contents of a directory by appending "/." instead of "/".
function rsync --wraps rsync
    # Don't break fish's rsync completions with our slash-stripping
    # https://github.com/fish-shell/fish-shell/issues/3337
    if status --is-command-substitution
         command rsync $argv
         return $status
    end

    # Strip trailing slash on "hi/" but not "/"
    command rsync (string replace -r '(.)/$' '$1' -- $argv)
end

Thanks to krader1961 and floam and faho for their suggested improvements.

What is the purpose to '--wraps rsync' if the function has the same name as the wrapped command?