Why produce ethanol?

Producing and burning ethanol in internal combustion engines is more polluting, less efficient than using electric vehicles. So this can't be it.

Producing and burning ethanol for heat is more polluting, less efficient than heat pumps or solar thermal energy. So that's not it either.

The article mention chemical industry and:

[..] building blocks for products ranging from fertilizers to plastics

This leaves fertilizers and plastics. So this would have to compete with other ways to produce fertilizers, plastic and plastic alternatives (cardboard packaging, wood, glass...)