It's just Kishimoto trying to make more symmetry between the powers of Naruto and Sasuke before they finally fight.
Now they both have a huge chakra-monster form, where both can shoot deadly objects (bijuu dama vs amaterasu shuriken), and their real body is safe inside the large chakra-creature so they can spam each other with terraforming-level jutsu without making any damage to the real bodies, that is necessary for long fights. I guess a chakra body can simply regenerate it's parts when it's cut or burned down, so they can continue to fight. Sasuke's susano will most likely also grow legs so it can run and jump around.
In human form the amaterasu of the EMS eye can instantly reach Naruto, but then Naruto in human form is faster than the raikage.
The only question for me is how will Naruto defend against the genjutsu powers. Sure he has now both chakra sensing and evil sensing abilities and also the 9-tails will help him, but if Itachi's eyes power up Sasuke genjutsu then Naruto will probably need some new magic agains that
