In answer to your question
Asked about it at a town hall in Pennsylvania, he said, “We have been trying to eliminate the penny for quite some time -- it always comes back,” joking, “I need to find out who is lobbying to keep the penny.”I'll be happy to tell you who is lobbying for pennies.
It's the poor of your country.
We depend upon the pennies that spill from the pockets of wealthy people such as yourself in parking lots to buy milk or eggs for our children, to collect enough to put one more gallon of gas in our cars so we can go to work - because we don't earn enough at our 60-hour-a-week jobs to buy gas or milk out of our paychecks.
If you're of a Biblical turn of mind, consider the pennies the gleanings of society.
The parking lot pennies have meant the difference between having heat one more month in winter or having it turned off for non-payment. The parking lot pennies buy aspirin for sick children. When your grocery budget is $20 a week, every penny is essential. Finding a couple of pennies means you have enough to pay the tax on the jar of peanut butter you'll carefully dole out for a week.
Before you consider eliminating the penny, please make sure you have no citizens who rely on pennies to survive.
If you dislike the penny so much, why not drop them in parking lots so your vastly underpaid citizens can use them?
A Mother Who Raised Her Family on Parking Lot Pennies