Dogme film, and the preceding Festen is also a great cinematic accomplishment indeed, it was The Idiots that opened the world's eyes to the Dogme phenomenon, and and made it the hottest thing on everybody's lips.
Including a few brief sex scenes which "showed it all" got it a lot of free publicity, as it was talked about on the news as well as weather reports. Although The Idiots was by no means the first to do so, depicting erect penises and full focus on spread legged women, was enough to start all new debates about what could be considered art and if showing people naked was actually offensive.
So, was it all a gimmick?
Yes, and no.
The nudity undoubtedly made the movie a few extra bucks at the box office, but the very few sex scenes also caused the raw Dogme form to take on a new level of realism. For if the sex scenes are real, could it be that the rest of the outrageous plot were not acted, but all real too?
Don't think that this is a full out porn-flick, though. The sex scenes are very few and last for only seconds. It's the rest of the plot and the great actors that makes it into what might be Lars von Trier's best film.
The sex scenes were shot with body doubles anyway.