How could alcohol be beneficial?

It's a slippery slope. Although there are health benefits associated with moderate alcohol consumption, it's not clear if it's truly alcohol itself or the lifestyle of the people who drink moderately that's making the difference. That said, the association appears warranted. Moderate alcohol consumption potential health benefits: reduces risk of heart attack and stroke; increases HDL (good cholesterol) and reduces blood clotting, which is probably the reason for a reduction on heart attacks and strokes. Additionally, just recently moderate alcohol consumption was connected to a lower risk of developing type 2 diabetes, gallstones and cognitive decline. It does appear that alcohol itself, and not the source, is responsible for the benefits. Moderate alcohol consumption is considered 2 drinks/day for men; 1 for women. One drink contains 14 grams of alcohol meaning: one 12 oz beer (5% alcohol), one 5oz glass of wine (12%) and one 1.5 oz of hard liquor (40% or 80 proof) are each one drink. The down side is that moderate drinking was recently associated with increased risk of breast cancer in women. Additionally, it can lead to excessive drinking. So keep it moderate or don’t drink*. All this said, moderate drinking appears to be part of a healthy diet.

*Although high consumption of alcohol (2-3 times more than moderate) was still associated with a reduction in heart disease, drinking more than 2-4 drinks daily dramatically increases the risks of consuming more, which not only will negate any benefits, but will also lead to disease and danger to others.