[Flieger]

Ethanol is more harmful to metal components since it contains that pesky hydroxyl group. Though it also makes Ethane into a liquid and more suitable for transport/storage, it also is more corrosive to (especially Aluminum) fuel system components. Or partially filled steel fuel tanks. Paper would not be harmed or know the difference.

The other issue is that it likes water. This can be good and bad. The ethanol can act as an emulsifier so that the water does not pool and end up going into the engine in one big gulp. More like free water injection. The bad part is that the water is in there to begin with and it is hard to tell how much since water and ethanol are miscible IIRC.