Detached chad can jam two cards together, increasing misfeeds. In some machines, detached chad can jam over the light or sensor, causing holes to not be read until the chad blows out of the way. Detached chad can migrate from one card to the next. People cannot count cards as quickly as a card reader, but a card reader is much more limited than a person in how it can handle and read a card. Any damage a card has sustained can confuse a card reader or cause it to malfunction.
People are better able to deal with such problems.
Cards that have had one or more trips through a high-speed card reader will appear different to a human reader than they would have when freshly punched by the voter. The results of the 2000 election show that it is now time move beyond this temperamental antique. Someone could vote for one of their family members, for example. Such amenities are not possessed by all citizens in the U.S. - Purely electronic ballots leave no paper trail, so electronic subversion of voting records could be difficult or impossible to detect. One approach that could provide the advantages without many of the disadvantages would be to provide Internet terminals in polling places.