Itachi using Izanami is a win/win. If it doesn't work he'll more than likely regain any lost sight from the jutsu due to his regeneration abilities caused by Edo Tensei and try something else. If it works he'll be able to release all of the Edo's, *along with himself*, and never have to tell Sasuke the truth which will continue Sasuke down the path of battling Naruto again. If the latter happens, Sasuke will try to ask Itachi about the truth and Itachi will go back into his coffin without giving a "good enough" answer and during that time Kabuto will sneak away.
I'm just wondering will releasing the Edo's send them back into their coffins and then they're gone or will it just release Kabuto's control over each one of them and they still need to be sealed?