It's less work for everyone involved, because they have to pick up their things fewer times.
The length of the line is determined by how many people are in it, not how close they are standing to each other. Being up in the business of the person in front of you doesn't make anything go faster.
Also it would be beneficial to a person joining this line, because it has less people in it compared to other wines of the same apparent length.
So the only people who are actually negatively affected are the ones who join other lines. And the neurotic who get irrationally angry at seeing the gap.