It is imperative you can vote without others knowing how you voted (at least here in the UK…). Electronic voting is inferrior to paper when it comes to trustworthness of recording an anonymous vote, counting the result and preventing mass vote fraud.

We already have a hardcopy ID to travel internationally or ID to drive vehicles. The risks of an electronic ID being easily copied would have to get me visiting other solar systems or driving a time machine before I considered it. Something tells me the paper options would continue working at first but eventually this idea will be forced on people.