The environmental impact and cost are of course important to consider, but for energy, there's also always the geopolitical aspect to comsider. Having the capacity to make fuels from plants means some independence from Saudi Arabia and Russia for the western world. The shock of 1973 has left its mark.
Having a huge supply chain for corn also drives innovation and scale in that industry, should corn become rare because of a drought, it would be relatively straightforward to redirect the corn supply into food.
When watching the video, what struck me as absurd is more the energy waste from meat production.
