A tailed beast uses its massive chakra reserve to turn a simple roar into a powerful force of pressure and destruction. The Nine-Tails' jinchūriki, Naruto Uzumaki, in his initial jinchuriki form used his roar to go through Sasuke Uchiha's Great Fireball Technique, and years later in his three-tailed form created a powerful sphere of destruction against Kabuto Yakushi and Orochimaru.
When used by Kurama itself, it's powerful enough to completely disperse powerful attacks like the Sage Art: Ultra-Big Ball Rasengan, and even knock back fully transformed tailed beasts.
