the breathing theory can only apply to the kamehameha wave 'jutsu', it's helpful when you shout stuff like "HA!, KA!' AA! ki!" to force more air out, but saying something like: 'Oniwabanshi shiki Kodachi nitoryu ougie!" (Aoshi's ougie) won't help your breathing, same goes with "kagebunshin no jutsu" and "double twisted spin of the wolf fang techinique!".

in naruto's case, it's only to help the viewers...