There is so much to be wary of here . . .
"Voatz also disputed claims its systems are vulnerable and untested"
But of course it would say that. I reckon we'll be reading about just how secure it is shortly after the upcoming election.
"Before going into the pilot, Voatz submitted the smartphone voting app to an independent security firm for review"
Oh really ? Which one ? And what was the verdict ? It's all very nice to hear these things, but if the company was available at securityreviewsforyou@gmail.com, then excuse me if I'd prefer a more reliable name.
"Voatz is not particularly open about how its system works under the hood"
A time-tested hallmark of quality in this domain, to be sure.
Security by obscurity, again. That works IRL, but not where computing is concerned. The only people who believe otherwise are the ones not competent enough to understand the true situation. Not telling people how your system works just means you're a hack who can't do things properly and you don't want people to know how shoddy your system really is.
A truly secure voting process is like encryption : you can know everything about how it works without having any means to subvert the system other than brute force - which is very time-consuming for little reward.
And blockchain ? Really ? With all the stuff I've already outlined it seems we have a Security Bingo winner. This will only end in tears.