> an out-of-place merge on a linked list would be pure madness

Absolutely. I'm not even sure how you would do such a thing.

I personally have found it interesting when considering the difference between an array of pointers and a linked list, simply because they both have the same overhead but one doesn't require allocating any more memory for a merge sort.

I basically agree with what you say (maybe bar it not being useful knowledge) but I don't think it's worth continuing trying to clarify my initial statement.