An even more extreme situation is with rapper. Rapper jigs have to go at a pace where there is nothing left of the tune but its metre - and if you did manage to insert any expressive phrasing the dancers wouldn't want it.

There was a workshop about playing for rapper at Whitby a couple of years ago. I went along, with the main question in my mind being "how can you do it without getting bored out of your skull?" - never got an answer to that.