What's to stop a maniac with a wrench "convincing" you to transfer all of your money to his bank account electronically?
Being coerced into voting for a certain party is a whole different problem, with different actors. You're not going to run the election again when the spouse of someone pressured them into voting against their will. How would you even want to prove it had happened in the first place? There's not going to be a paper trail without giving up voter secrecy, which is yet another problem.