In Buddhism, is “nothingness” ever more than a temporary meditative state?

In many early Buddhist suttas (Pāli Canon), one of the formless absorptions is ākiñcaññāyatana (“the sphere of nothingness”). It is described as a refined state of concentration, attained after transcending sensory form, space, and consciousness. What I’m trying to understand is Once one attains the sphere of nothingness in meditation, is “nothingness” regarded doctrinally as ultimate reality, or is it always considered a conditioned, temporary state? How is this “nothingness” distinguished from emptiness (suññatā / śūnyatā) in Buddhist philosophy especially in Theravāda vs. Mahāyāna?