> Unlike many other sorts where if you interrupt it before the last step, you get total nonsense.

which ones you have in mind? and doesn't "nonsense" depend on scoring criteria?

selection sort would give you sorted beginning, cocktail shaker would have sorted both ends

quick sort would give vast ranges separation ("small values on one side, big on the other"), and block-merge algorithms create sorted subarrays

in my view those qualities are much more useful for partial state than "number of pairs of elements out of order" metric which smells of CS-complexity talk