For fuck's sake. The thread is about "Is Enma power-up ITSELF or not" IT'S NOT. Power-up is better CoA (and physical stats because it's training after all) through TRAINING with Enma. Enma is a tool that helps Zoro get a power-up, which is better CoA.
After training, take away Enma from Zoro and give him Shusui, it's not gonna change anything. His Haki, DC, Skill, PS would be the same, just like with Enma.