I don't get what's wrong with paper voting. If it takes 3 days instead of 1h to get the votes, I think it's worth the wait since elections are pretty important

I don't get what's wrong with paper voting. If it takes 3 days instead of 1h to get the votes, I think it's worth the wait since elections are pretty important and with paper you can do a recount, find physical paper that's been thrown in the trash (happens every time in Italy), etc. Also, these corporations seem to have a strong political bias, and how do we know they're not injecting their software with backdoors that would allow to manipulate results..?