It really depends on what you think is going to happen in the future.
1. Do you think the melt ban will be lifted anytime soon? If yes, then keep saving the pennies. If not, then saving copper pennies might be a waste of time.
2. Do you think that the price of copper will increase? If so, then hoard pennies because there will always be people who will buy pennies in hopes that the melt ban will be lifted. If you don't think the price of copper will increase than saving pennies would be a waste of time.
3. Do you expect the collapse of the US dollar or revaluation? If so, then consider hoarding (copper) pennies because in many countries experiencing hyperinflation the banknotes get revalued while the coins get revalued at the same rate (for example, if the US decides to revalue the new dollar at 2 old dollars, each cent would double in value if they didn't withdraw the coins). If not, then the coins would most likely not be legal tender (or wouldn't be cared about being such a small value) and they would be legal to melt.
4. Do you have a place that will buy copper pennies at a rate above face value? If so, then it might be worth it to make some instant profit as you are searching penny boxes.
The answers to these 4 questions depend on each person. No one can know the future, if I knew with certainty that the melt ban would be lifted 3 weeks from today, I'd say save all the copper pennies you could and search 20 boxes a day. If I knew with certainty that the melt ban would only be lifted 50 years from today or that the price of copper was going to plummet to 25 cents per ounce, I'd say don't save them. But no one knows the future and so its all based on opinion and ease of selling them. Yes, copper cents do take up space, but they have a lower value/space ratio so you don't need to secure them as tightly as silver or gold.