There's a difference. Akasha, the origin of all things, is the original personality housed in the body (rather than Shiki (female) and Shiki (male) which are personalities housed in the mind).
"Usually, a life begins connected to the Origin until the connection is severed at birth, and even if somehow a life remained unsevered, the body's personality itself should not become self-aware, but the Ryougi family's special trait allowed it to survive and survive with intelligence. Because she has no interest in anything however, she usually remains dormant within Shiki."
Her sword skills was selfsuggestion which enforces her physical and mental abilities. It was Ryougi's usual personality wielding it, not Akasha.
See, if Akasha were to use her powers, she could recreate reality to her whim.
"Spiral of origin, its where all cause and effect begin, where everything and nothing exist, that is my true identity. Even though we are just connected, but since I am part of it, I too am an equivocal existence, right? That is why I can do anything..hmm like restructuring the laws governing atomic matter, or go back in time to change the evolution and development of all life, to reconstruct the orders and laws of this world is easy for me too. Not making change to the existing world, but rather annihilate the old one with a new reality."