First position, last position, and length for an array of [1, 2, 3].

  0-based: 0, 2, 3  (0, n-1, n)

  1-based: 1, 3, 3  (1, n, n)

Having the last position and the length be the same seems to fit the common intuition, like how children count: "What is the position of the last thing" and "How many things do we have?".

So it may make the language easier to learn. On the other hand, it may make the learner struggle to pick up most other languages which use 0-based index. I suppose it's been argued in depth on both sides..