Another downside of corn starch, making cactus the favourable choice, is that corn still has a significant environmental footprint. For example, corn has to be grown in a certain climate on a farm, and be watered often. This space and water could be being used to grow foods to eat, and leave the plastic-making to the hardy cacti that can grow pretty much anywhere, without much water at all!
The final material isn’t as long-lasting as fossil fuel plastic, but can certainly be used to replace the plastic we only use once. Such as single-use cups and cutlery, or take-away pots. And, unlike corn starch or other compostable materials that could be used, cactus will break down much quicker, and even in a home composter!