- It's a carbon sink,
- it's lightweight (reducing transport emissions)
- it takes very little energy to produce compared to glass or metals which require furnaces
- and has very little carbon emissions during production unlike paper packaging which has a huge carbon footprint.
The only problem with plastic is that it doesn't always make it to the proper disposal place. This isn't Coke's fault, people can just as easily dump a paper carton in the street. I think you'd get more dividends by ensuring the public has the motive (stick or carrot) to not dump their garbage into waterways, and in very poor countries, funding sanitation infrastructure.