I mean, it's a polymer all right, so is starch, but the point is to use something watertight but still biodegradable. Other petroleum derivatives could be used

I mean, it's a polymer all right, so is starch, but the point is to use something watertight but still biodegradable. Other petroleum derivatives could be used as well, but I tend to think of beeswax as proven to be food-compatible, though I am not sure if this was rigorously tested. I thought answers to my comment would rather focus on the low melting point, making it hard to use for hot beverages (though 60°C is high enough for drinks). You are right of course, but the article mentioned PLA, IIRC? Reading more on this topic, it seems that PLA is biodegradable, but only in industrial, high temperature composters?