Currently, the use of Anatman is to halt Twin Snakes from Expiring during transition phases since the MNK skill adjustment. It works as a DPS gain, albeit you need a decent level of optimization for it since you're competing with a bunch of other skills to use during disengages and transitions.

It's more widely used, however, as a skill to 'look cool' for most players however.

Would be nice if Anatman became our Power Up form though.