Lack of tail pointer impacts performance because: 1) Requires traversing entire list for enqueue, 2) Results in O(n) time complexity for enqueue, 3) Negates queue's advantage of O(1) operations, 4) Forces inefficient list traversal, 5) Particularly problematic for large queues, 6) Can be fixed by maintaining tail reference, 7) Shows importance of proper pointer management, 8) Common beginner implementation mistake.