I guess the Swedish CAA trust people to follow the rules. Of course you can choose not to follow them as with any rule. But they give those who follow them the confidence that they will under no circumstances fail a test should they be asked to take one before flight.
The question about the 8 h and 0.2 limit is quite simple really. Since you are under the 24 h period you should not "build up" alcohol in you body. Meaning that you can't consume a bottle of wine but a glass to lunch and a beer or maybe two to dinner is ok. Knowing that, you just have to make sure you have that beer or two at the latest 2 h before the 8 h limit. I think common sense is the key here.
Well I guess technically you can drink a whole bottle of wine (UK law) say 10 h before your flight. So if you don't have an early departure or are an early drinker you might get away with it, but is it wise? Even though your blood alcohol level has passed below the 0.2 limit there are other things to consider. Someone wrote that he/she would rather have a co-pilot who had a beer too many the night before but got a good nights sleep, than someone who slept bad. The fact is that when you have alcohol in your body you don't get a good night sleep. Your liver is working overtime and even though you do actually sleep, it's of bad quality. So with drinking often comes fatigue.
Personally I think that the rule max 1 or 2 drinks on a night stop seems reasonable and safe. If anyone need to have more than that when working the next day maybe a look at its drinking habits would be a good idea.