Surely the mechanisation of vote fraud, like all mechanisation, is about the multiplication of effort. To suborn a national election by mis-counting hand ballots, and do it by a small enough and widespread enough margin to not get caught, you need to suborn at least one person per voting precinct. How much easier, to suborn one person per voting machine manufacturer? or perhaps someone with warehouse keys just before the machines are sent out?

Also, paper ballots can be re-counted, as long as you've kept ballot boxes under reasonable physical security. So actual mis-counting, as opposed to stuffing, would come up on a re-count. There's no audit trail for an electronic voting machine, unless you count ones policed by the same people you didn't trust to make the voting machines work right in the first place.

Peter