Anger Management
'Phew! No wonder Arthur wanted this power.'
Eren said as he watched Claho shed his epidermis and start transforming into the creature of wrath. He had remembered that Eliza had stated that Arthur was eyeing the true reward of Purgatory from the very beginning. Now he understood why that was the case.
It wasn't that Eren could grasp everything about the rankers' experience through his ability. He could only retain a portion of those experiences and make them his own. But the fact that he could do that was revolutionary itself.
Eren could now practically master many weapon arts and battle styles if he accumulated and grasped enough experience about them the way he did. Then all he needed to do was fine-tune them with some real-life practice. This is easy. As a result, he would be able to master a particular weapon or battle style within a few weeks. This is in contrast to the years normal ranked soldiers spend in training.