From what I understand of the economics and moral aspects of ethanol it's useful as a performance fuel - used in the USA in particular for many years especially in oval racing - for added power from vehicles with engines appropriately built and tuned. Drag racing comes to mind.
Pretty poor on any other basis and most likely would not be in use if not mandated by governments.
I think E10 might be in fairly wide use but not necessarily labelled as such. It may allow fudged national CO2 emission numbers. Numbers are everything.
I don't think we have E85 (or at least I don't recall seeing any) in the UK.
I think it sells where the after tax price is significantly reduced compared to regular fuel grades because people think they are getting a price bargain. I wonder if they really are?
Here is a link that sort of discusses the economics aspect related to a flex-fuel car.
https://www.popularmechanics.com/car...se-to-buy-e85/
I also recall that when hi-Ethanol content fuels were introduced in Scandinavia Saab and Volvo introduced special Bio models designed to work with those fuels. It might have been simply a ruse to tap into potentially higher profit margins by those who could afford to be virtue signallers but as I recall they used different components - especially anything related to rubbery pipes and some metal items - to reduce the adverse effects of the ethanol.
As for the economics .... a decade or more age I read that if the source cropp was grown more than 50 miles from the ethanol product plant and the resulting fuel was used more then 50 miles from the plant the real cost of manufacture and distribution, compared to fossil fuels, was not competitive.
So the conclusion then would have been that it would be a great option if you could harvest material and distil the ethanol yourself but somewhat poor if not. Likewise maybe ok if doing your own car maintenance but not so good if paying others.
Whether any of that has changed I don't know. It might be worth a dedicated thread ?
ETA: If you have 25mins to spare here is an interesting take on things from Australia.
https://www.youtube.com/watch?v=ltWcgiCm4NY