I enjoyed Iosif Pinelis's slick answer to another MO problem using the Henstock–Kurzweil integral. Are there other examples of problems whose statement does not explicitly involve the Henstock–Kurzweil integral, but which can be solved more elegantly using the Henstock–Kurzweil integral than by more conventional methods?
I'm sympathetic to the notion that the Henstock–Kurzweil integral should be more widely taught as a theory of integration (at least in dimension one), but I'd like to see more examples of its usefulness.