hi @MortenSI !
I haven’t seen these type of running sushi restaurants outside Japan either. (Maybe at some places owners don’t trust the customers enough to calculate the bill only by the plates… 
)
About the quality: it’s true, Japanese are always aiming to the highest standards, even in the smallest market hall stalls; …and of course the ingredients (I think the rice is even more important than the fish!) are also a prime factor. I would advise to eat sushi only in good restaurants in Europe, because the cheap chain places or the pre-packaged bento boxes are only going to ruin your appreciation of good sushi.
Hope you’ll make it into Japan and have a try there! 