I think its not telling you that alcohol gets you drunk but showing how quickly a 5% beer can get you drunker than a 4% beer over the course of a few beers. People may think that its just 1% extra, it can't be that much more but when you factor in the alcohol metabolization speed, that extra 1% adds up. The extra alcohol in the bloodstream will make the buzz last longer.

In short, you might be ok to drive an hour after a couple 4% beers but not ok an hour after a couple 5% beers despite just the perceived slight increase in alcohol percentage.

The thrust of the article for those that read beyond the headline is that the difference in intoxicating effect beyond slightly below average strength beer and slightly above average strength beer is much greater than you'd anticipate from simply looking at the %ABV figure.

I doubt even many regular drinkers suspect that drinking 5% beer leaves them with around twice as much alcohol in their bloodstream as drinking 4% beer (although regular drinkers tend to drink fast enough to narrow that gap) Certainly would have been useful to know that back when I chose beers based on optimising for units of alcohol per £!

That's not the point of the article. It's saying that because of the rate your body processes alcohol, seemingly small differences in ABV can leave much more unprocessed alcohol in your body than you'd expect.

Are you saying that the answer to the question in the article was obvious to you?