-Succubi have all their powers reset when they go back to Hell after having their physical form destroyed. They will go back to "the end of the line" so to speak.
-If that succubi had power, she'll be humiliated by the succubi she once commanded and they will make sure she's never going to rise again, because they know of her potential.
-If she had a bad relationship with the new duchess, now that she is powerless, she might be treated terribly, to the point of exiled, like Nemorosa, from Warlock Saga, who stole the whip of lady-black horn and faced the wrath of the Duchess Rafflesia.
-She'll lose access to all her commodities, like feeding on the best males, servants, influence, connections, power. This alone is a nightmare, literally hell to any succubi.
-In a way, it would be for the better to have a "final death".
-And yes, up until now, there is no way of completely destroying an angel or succubi. They will always go back to Heaven/Hell to take form once again, but with all their powers reset.