I have always understood the effect of alcohol as
@Antje77 explains - it stops the drip of glucose whilst processing the alcohol.
I have never heard of it “stretch the effect of carbs over a longer period”. This does not reflect my experience. With Type 1, if this was the impact, I would need insulin later when drinking alcohol and I have never needed to do this. However, I have experienced hypos the day after drinking. Therefore, I reduce my basal insulin which is taken to work with the glucose dripped from the liver throughout the day.
@ianf0ster I am intrigued by your theory. Can you provide a reference so I can read more about it?