Well, you can convert any sorted dictionary to an insertion order dictionary by copying it over, but that does the make the original example pretty clunky.

I guess a better use case is if you needed some sort of priority/FIFO logic along with indexing. Hard to think of something that doesn’t feel contrived, but I guess imagine having a queue where determining membership or updating fields of an element based on ID can be done in O(1) for any element?