Contrary to popular belief, in state or nation-wide elections paper is a safer way to vote than electronics because the former is simpler and thus easier to verify by the general public.
Most people don't realize how hard it is to beat the transparency and simplicity of a physical ballot box. It can be inspected by the public at the start of the day so anyone interested can verify it's empty and people can keep an eye on it during the day and see if anyone tampers with it. Then at the end of the day it's important the votes are manually tallied right after the ballot box is opened. This makes the process transparent to most people in society and assures the highest level of scrutiny and confidence that the vote and vote count are legit.
It's hard to replace this with anything more complex i.e. electronics.
For a recent discussion see: