Why not? Isn't he Chaden for a reason? Assuming that Enma has a thirst that grew with Oden, which then got used to his haki pool and now has to get used to another user's haki pool is so much more convoluted than a simple -> Chaden, which is exactly how he was portrayed. As an absolute Chad, EVEN at 10 years old.
We've been told from 2 sources Swords can go in battle and it's also a testament to the swordsman, so there's no reason for Enma to stay stagnant while Oden himself is improving.