Computers anywhere in the vote casting process introduce new, additional failure modes. These modes may be intentional (hacking) or unintentional (misconfiguring the paper size of the ballots). They may be mundane (power failure, out of ink) or esoteric (logic error). Even computerized counting has a nonzero error rate (so does human counting, but that can be challenged by human observers).
Computers add cost for acquiring the computers and training the staff. Computers add complexity and complexity usually reduces the reliability of a process. In a process like voting, that also reduces confidence in the process. This and the cost alone make it unclear why anyone would want to spend the money to electronicize vote casting and counting.
People have been voting without benefit of electronics for thousands of years.
In the vast majority of countries where paper ballots are used and counted by hand, the count is almost invariably completed the day of the election.
Conversely, in the US, where we spend lots of money to acquire, maintain and operate computers to “assist” in voting and vote counting, now we have many jurisdictions who say that they cannot complete counting on Election Day.
It boggles my mind that anyone still supports involving computers in vote casting and counting.