They were also able to fight by changing only part of their body but for that they had to master this transformation perfectly well, and it could be troublesome doing that during a fight, especially when you had no idea how strong your opponent was.
And more importantly it was very taxing on chakra and so it wasn't a good option.
After the last fight, which wasn't really one because Dante hadn't even fought, he was sure he would need all his might to be able to take down this young wolf.
The crowd was really surprised as it was very rare to see their Alpha using their final wolf form, and this confirmed what everyone had already understood, the grandson of their Supreme Alpha was no ordinary Werewolf.
Axel the wolf of course could feel all their emotions, and after the first fight, Kevin had lectured him a bit, reminding him that he had to be careful not to scare them too much.