it doesn't have to be used for all communication.
assume a world where all your emails are archived in publicly accessible databases. you've lost privacy, but could it still be a useful tool?
send birthday emails. send your friends funny cat videos.
you don't have to use email for everything you used it for before -- you can just use it in different ways. i would still like to be able to near-instantly communicate with relatives across the world.
i know bacon clogs my arteries and making bacon has a terrible environmental footprint relative to eating only grains, but i love it.