A: For small arrays. I would add: particularly if you need a stable sort algorithm, which is either complex (Block Sort) or uses O(n) space (Merge Sort).

Doesn't Shell sort also have the property of the exchanges leaving the array more ordered than before?

https://en.wikipedia.org/wiki/Shellsort

Shellsort can be regarded as an improvement over either Bubble Sort or Insertion Sort.

Well, I used Bubblesort to sort the results of lottery draws because it was very easy to implement.

bubble sort is sometimes used in information retrieval use cases for reranking top k based on some signals, especially specific to a user profile. I feel heap sort comes up as well, yet neither are necessarily the most efficient.

When you get into C code sometimes you know the most thinngs that will be in the priority queue is like 3. So bubble sort is fine.

You can also do something like a calendar queue with bubble sort for each bin.

Used it a couple of times when n was inherently very low.

And while I've never hit a case I would think it would have merit with data known to be pretty close to properly sorted.

It's way easier to remember and program

When I was playing The Farmer Was Replaced and needed to implement sorting, I just wrote a bubble sort. Worked first time.

to compare other sort algos against it

it's great if you need to sort in the face of unreliable memory iirc