The problem with pen and paper elections is that they rely on honest counting.
It's true that it's easier to manipulate a terrible digital system but that doesn't mean pen and paper is safe.
Block chain technology would offer an open record that couldn't be manipulated, something paper does not.
I mean, I live in Denmark, one of the least corrupt countries in the world and we've had politicians caught changing votes with a pencil and an eraser during the count.