I'm not exactly sure where he's going with this. Of course it's worth the least, it's a freaking penny. It's the smallest denomination of currency. All others are naturally worth more.
Where he's going with this is that compared to the coins of other developed economies, the U.S. penny is the smallest in value of those currently minted and circulating. It is worth less than the Canadian penny, the Euro cent, the British pence, the Japanese yen, the Danish 25 řre, the Hong Kong 10˘, the Iceland 1 króna, the South Korean 10 ₩, the Taiwan half dollar, the New Zealand 10˘, the Australian 5˘, the Norwegian 50 řre, and the Swiss 5 centimes. It's also higher that in value than the smallest coin of a number of second tier economies such as the Brazilian 5 centavos, the Chilean 10 pesos, , the Slovak 50 halierov, and the Latvian 1 santīms.
Because the dollar is weak right now.
If you use this logic, then Europe should get rid of the €.01 and Britain should drop the pence piece. One euro cent spends in Europe just like a penny in the U.S. You can't use the whims of the currency exchange to justify dropping types of coins.
I would argue that the actual value of a penny is higher than the value of a euro cent, as the one euro cent piece is quite small and pathetic and annoying. (the 2 euro cent piece is actually closer to penny sized)