You pretty much need these on 6 packs because....
1. Most people aren't skiing in a group of 6 so strangers are sharing a chair. Lot of times strangers who will end up on the same chair don't line up in a nice even line with the people who they will eventually share a chair with- they have personal space concerns so hang back or forward.
2. In a standard queue it becomes really tough to figure out how many people are lining up to which chair.
3. "Cattle Chutes" make it clear who and how many are getting on that next chair. If you don't have a space, you mis-counted.
4.Counting to six is 50% more difficult than counting to 4.