It's not about actual vulnerabilities (although it may also be), it is about the general public's confidence in the legitimacy of the election. Voting machines

It's not about actual vulnerabilities (although it may also be), it is about the general public's confidence in the legitimacy of the election. Voting machines do not instill confidence, and that is a bad thing for a democracy. I don't care about the microcosm of improved efficiency. That's not the thing to try to make ultra efficient at the cost of legitimacy.