Yeah, well.
That's obviously the simple way to swap 2 items, but problems appear when for example:
1- We have a "bouncing-swap" where the target item should be swapped with a third one and so on. E.g. swap 2 with 5 and 5 with 3.
2- We have several swaps targeting the same slot: swapping 2 with 5, 4 with 5 and 1 with 5, what would mean: swap 2 with 5, 5 with 4 and 4 with 1 (back to problem nr. 1).
Tbh, Lobster, I could've done that, I'm not that n00b, you know