Actually, you're right, it's the larger values of k where this might make a diff...

extension on Feb 1, 2010 | parent | context | favorite | on: Nth-to-Last Element in a Singly Linked List

Actually, you're right, it's the larger values of k where this might make a difference. If the list items are scattered in memory, the cost of the buffer increases very slowly with k compared to the cost of hitting those extra k/2 items.