First I agree with you that I don't get a lot of YC startups, including the food selling machines at their current state. I do think that one of the more inefficient aspects of life is how humans handle food, from producing, transporting, storing to cooking/eating. There are just too much waste in every step of that chains. More depressingly, this is waste that doesn't necessarily go back to support the environment like the salmon leftover from the bears. Improving efficiency in any step in this chain is huge for humankind, and potentially worth a lot of money too. I don't know if the YC food startups have that goal in mind, or they are more going for the "oh this is cool" aspect.