What it teaches
Sorting, and the fact that it can be done with one repeated move. Swapping neighbours is bubble sort performed by hand, and a child who does it a few times has done a real algorithm before ever meeting the word.
The screen says how few swaps the row needs, and that number is exact: the fewest swaps any sorting can take is the number of pairs that start out the wrong way round.
What to look for
Four towers is a puzzle and seven is a genuine one. The counter showing how many pairs are still out of order is the thing to point at: it goes down by exactly one on every useful swap, and not at all on a wasted one.