You as an election judge may be honest, but not all of them are. At least one election in Mexico was stolen by computer manipulation by the central election commission. It appears that Bush stole the 2004 election through fiddling with the electro-optical vote counting machines. I've seen evidence that other elections in the US were stolen thru voting machine manipulation.
Whatever the technology, we cannot rely on the election authorities to be honest. So we must reject technology that forces us to rely on this.