Command Pattern for Undo feature Question

Is anyone confused about Mosh’s implementation of undo using the command pattern? His explanation was that this is better because it’s less expensive but the way he’s implemented the command pattern for undo feature is actually doing the same thing? If you call boldCommand.execute() multiple times, you are storing the state unnecessarily. I guess it works if users are prevented to call execute more than once? is anyone else confuse like me too?