Zoro said mastering Enma is him only cutting that tree if he only wants to cut the tree and not cutting cliffs all the time.
Thats all that was stated about what Zoro was supposed to do from the get go. He wasn't learning some super slash ability. The sword already forces people to do super slashes. Literal fodder could just touch the sword and bam they do a super slash.
Zoro as a master swordsman is the one who stops the sword from doimg a super slash and that's what proves he is better than those fodder swordsmen, he can actually make it not do excessive damage.
That's all that was stated Zoro was doing and had to do.
The haki draining only existed for Zoro to get haki training and doesn't actually affect combat unless Zoro hasn't mastered the sword. As we saw with Oden, complete mastery of the sword just turns it into a regular sword. It's just as effective as any other sword of the same Grade. Meaning as I said before, Enma isn't a power up. It is of the exact same grade as Shusui and can even be argued to be a lesser sword since its not Black. The oniy reason its a plot device is to be a training wheel for Zoro to get stronger but oce in actual combat, it is supposed to function like any other sword.
Thats all that was stated about what Zoro was supposed to do from the get go. He wasn't learning some super slash ability. The sword already forces people to do super slashes. Literal fodder could just touch the sword and bam they do a super slash.
Zoro as a master swordsman is the one who stops the sword from doimg a super slash and that's what proves he is better than those fodder swordsmen, he can actually make it not do excessive damage.
That's all that was stated Zoro was doing and had to do.
The haki draining only existed for Zoro to get haki training and doesn't actually affect combat unless Zoro hasn't mastered the sword. As we saw with Oden, complete mastery of the sword just turns it into a regular sword. It's just as effective as any other sword of the same Grade. Meaning as I said before, Enma isn't a power up. It is of the exact same grade as Shusui and can even be argued to be a lesser sword since its not Black. The oniy reason its a plot device is to be a training wheel for Zoro to get stronger but oce in actual combat, it is supposed to function like any other sword.