There are multiple people watching ballot boxes during the election. Best part - anyone can signup to watch and later count them. It's dead-simple job and any nut can easily do it. On top of that, all major parties have their own people watching each other. You'd need massive operation to mess up even single voting outpost.

Meanwhile with e-voting we'd loose transparency. Non-tech people would be completely out of the loop. Many tech people would have hard time inspecting hardware and source code too. Let alone there's no bullet proof way to ensure code on the machines and machines themselves weren't tampered.

E-voting is a wet dream of any conspiracy theorist...