Paper ballots satisfy both of those properties. What problem are computerised ballots trying to solve? I've seen cost mentioned but haven't seen any evidence that it's cheaper. I imagine that it's mostly about getting the election results faster but is that really a goal of an election? Speed over accuracy?
You can get the speed of e-voting with paper ballots if you tally up the totals twice: once with a scanner when the ballot is put in the box (appropriate design of ballot and box required ofcourse), so you get immediate digital results, and once with manual counting to give the vote legal standing. The fact that only a manually counted result would have legal standing ensures nobody will see the point in tampering with the digital counter.
I would agree that there's no reason to have e-voting instead of paper ballots. The only possible excuse I might imagine for e-voting is that it lets people vote from home which enfranchises more voters, but that would just lead to a wave of vote selling so...
Accessibility is one area where paper ballots perform very poorly.
The Help America Votes Act, which spurred much of this new voting technology, specifically says voting places and ballots should be accessible by voters with disabilities such as the blind. This is very hard to accomplish in a secure, protected way without a machine. Some polling places have paper ballots for most, and machines reserved for the disabled.
