Is it true that ethanol can have some positive effects?
Alcohol has caloric value.

First worlders today have a wealth of high calorie food choices which make the caloric value of alcoholic drinks either irrelevant or detrimental.  But it was not always this way. In circumstances where other caloric sources were limited or unpalatable, alcohol supplied calories needed to supply the energy demand of workers.  Persons working energy-intensive jobs (such as field labor or factory work) have historically supplemented calories from food with calories from ethanol.  The below excerpt discusses the dietary habits of metalworkers in the late 1800s.

Drink, Temperance and the Working Class in Nineteenth Century Germany


  Despite the overall improvement in dietary standards of the previous
  two or three decades, the situation of these Manheim workers suggests
  that alcohol remained an essential part of the working-class diet. If
  provided necessary calories in palatable form. The sharp flavor of
  alcoholic beverages could add spice to otherwise monotonous fare,
  providing a sense of warmth and fullness even when meals were cold and
  unsatisfying. Perhaps most important, alcohol provided energy in
  concentrated form. Alcohol, whether in the form of beer or spirits,
  enabled workers to reduce the sheer quantity of food that had to be
  gotten down each day. The distinguished physiologist Max Gruber
  calculated that a worker who consumed even a 10th of a liter of
  schnapps with the meal could come up with no energy loss, reduces
  potato and rye bread consumption but some 288 and 122 g
  respectively.”Try eating a kilo of black bread or two or more kilos of
  potatoes day after day”, Gruber told his well fed middle-class readers
  in 1888, “and you’ll discover what a relief it can be to substitute a
  pungent and stimulating beverage for a 10th of this mass”.


The health benefit of alcohol consumption here would be that of not starving in situations of high caloric expenditure.   calories are concentrated as compared to carbohydrates and distilled spirits also have an indefinite shelf life - not true of grains and potatoes.