Regular plastic is made from petroleum, a non-renewable resource. PLA plastic is made from crops from which lactic acid can be derived, primarily corn in the United States, but from other crops overseas, with potential for even better crops in the future.
If you’ve heard about small farmers razing sections of the rainforest in order to grow ever-larger crops of bamboo, or if you’re horrified about the state of soybeans in the U.S. after watching Food, Inc., then you know that industrial crops definitely have their problems, too. But corn-based products have the potential to be (and already are, in my opinion) far better environmentally and economically than petroleum-based products.
Of course, saying that something is better than petroleum isn’t really saying a lot, is it? It still takes energy and resources to manufacture PLA. It takes energy and resources to compost or recycle PLA (and it can be composted and recycled, with plenty of caveats for the present). It takes energy and resources to grow the crops that make PLA, and energy and resources to re-make PLA from its recycled components.
But if you must use plastic, then this is the plastic to use. PLA can be grown sustainably. PLA can be recycled. PLA can be composted in large-scale facilities.
PLA can be made from resources that don’t encourage wars to be fought?
Well, we’ll have to see about that one.