My understanding is that they are starch and cellulose, so I'd expect them to eventually completely degrade like any other plant material. I'm not an expert, but that seems to be the point of products made with it.
Our liquor store (LCBO) used to have bags made from the same stuff. When our provincial premiere got everyone to charge 5c for each plastic bag, they just stopped using it entirely and went to paper bags. I liked those original compostable/recyclable ones because they were less stretchy and therefore less likely to break than normal plastic grocery bags, and way easier to carry because of the handles.
But the same reasoning applied - it was more expensive than paper bags, so that's all they use there now, too.
Our liquor store (LCBO) used to have bags made from the same stuff. When our provincial premiere got everyone to charge 5c for each plastic bag, they just stopped using it entirely and went to paper bags. I liked those original compostable/recyclable ones because they were less stretchy and therefore less likely to break than normal plastic grocery bags, and way easier to carry because of the handles.
But the same reasoning applied - it was more expensive than paper bags, so that's all they use there now, too.