I've already explained elsewhere in this thread that it's easy to make this system also deniable, so that you cannot be extorted. As for buying votes, the deniability would make it equally difficult to prove you voted a certain way as it is now.
It's deniable afterwards, but not during. At some point you reveal to the voter a way to map their vote to an anonymised 1 or 0. That point is vulnerable and that point will be where someone expects you to show them something.
It is exact opposite of what is wanted.