so there's not powerup for zoro with exchanging shusui for enma? then whats the fukin point of the scene where enma took zoro haki and made his arm thin as f?
The point of the scene is to show how the sword needs to be tamed otherwise it will be a hinderance that will absorb the user's haki more than the user actually wants to give.
This is forcing Zoro to train his haki in order to be able to use Enma.
Enma was initially a downgrade as Zoro couldn't control it. (A master swordsman should be able to cut anything he wants and not cut anything he wants, Enma made this impossible)
However, after Zoro gets better Haki control, Enma will be as useful as Shusui.
Shusui is the national treasure of a country full of swordsmen. Enma on the other hand isn't even more special than the other sword Oden had.