I afraid I didn’t explain myself very well. The front end machine would only mark the ballot for the user, minding overvote and stray marks. The tally would be done by a machine or human reading the ballots.
Scantrons are a more effective way of doing this. My local officials offer a lot of excuses as to why they aren’t any good but the unspoken one is that they can’t hijack an election with them.
If the ballot is delivered to the user’s hands in a way that they can read and understand and that is the ballot that is counted, at least there is a better chance that the election might be fair.