That's one point of view. Another is that ethanol is in fuel for purely political reasons, mainly to support the producers of the main supply of ethanol, which is American farmers. A third is that it's a complete scam. For instance:
https://www.detroitnews.com/story/op...rs/1483191002/
As for the octane properties, what it really allows is much higher compression and boost than straight gasoline, without the dangers of lead. NASCAR uses it for that reason. Most passenger vehicles don't have high enough compression ratios or atmospheric boost to get much, if any, benefit from it.