On a base level, the swords are the same. Enma is just harder to use at the start since it forcibly releases haki from the user, while Nidai Kitetsu is probably more circumstantial rather than tough to handle. It might be similar to the Sandai Kitetsu, which attempted to cut without Zoro’s permission, but it could also be that it attracts misfortune towards the wielder, so nothing that’s immediately noticeable like forced haki consumption or acting on its own.