Experts have argued that if a citizen is able to verify his vote, they will be able to sell it. Epitome deals with this problem, as future extensions will be able to prevent this problem while simultaneously allow users to verify that their votes were counted as cast.
Moreover, in order to successfully make an impact, an individual or a corporation would have to buy hundreds or thousands of votes, increasing their risk of getting reported to the authorities. Even if one would somehow manage to buy hundreds of votes with none of the people making a report this would cost significantly more time and money than it takes to bribe a handful of elected politicians.