There must be a downside to that technique.
Why you ask?
Well Hashirama wanted to end his fight against Madara because he wanted to help the Fodder Allience against Obito.
He told Madara to stop but he kept on going. That would've been a good moment to take out Shinsuusenju to deal with Madara and after that he could go back to the fodder alliance. Why wouldn't he do it? He is an Edo and he is already in Sennin Modo.
Well my guess is that Shinsuusenju was a jutsu he only could use once. When he made up his mind to finish Madara off he used it, and he probably can't use it anymore.
What other reason could there bee that he still didn't bring it out?o
Why you ask?
Well Hashirama wanted to end his fight against Madara because he wanted to help the Fodder Allience against Obito.
He told Madara to stop but he kept on going. That would've been a good moment to take out Shinsuusenju to deal with Madara and after that he could go back to the fodder alliance. Why wouldn't he do it? He is an Edo and he is already in Sennin Modo.
Well my guess is that Shinsuusenju was a jutsu he only could use once. When he made up his mind to finish Madara off he used it, and he probably can't use it anymore.
What other reason could there bee that he still didn't bring it out?o