1) "Governments are instituted among men, deriving their just powers from the
consent of the governed." -- Declaration of Independence
The voting process should be transparent and understandable to all. The use of our human senses, eyes or ears, are our best measure of truth and reality. HCPB are the most basic form of that.
2) Democracy is so important that it should not be subject to time limits when determining the winners of elections. Whether or not ballots are scanned as "quick, preliminary answer" as to who won, only the HCPBs are official, with the actual count being done at the place the ballot is cast.
3) Voting is the essence of Democracy.
HCPBs results in a deeper tie between citizens and their government/nation than machine voting can do, in much the same manner that Selective Service and jury duty does.
4) Voting machines have software. We all know software has "glitches". Paper ballots do not.
6) Voting counting software has been, and can, misprogrammed. Such cases have cost voters their votes. Paper ballots are not vulnerable in that way.
7) A single voting machine error can affect an average of 1000 votes per race and per issue per machine. (HCPB, at most, lose the vote of the one voter who mismarks their ballot.)
8) Machine voting mechanisms require temperature-controlled (air-conditioned) environments for storage of the machines between elections. This is expensive and, unnecessarily, uses natural resources.
9) Hand counted paper ballots don't jam in optical scan voting machines during inclement weather.
10) A recent Zogby poll found that 92% of likely voters agree that citizens have the right to view and obtain information about how election officials count votes. HCPB are the best, if not the sole, method by which this can be accomplished.
12) With HCPB no experts are needed to explain to the public what is happening in the vote, the audits or the recounts.