Personally I haven’t been able to get good results using Film Negative. Maybe it works better with some negative films than others. Yes, with the normal tools in RT, you need to apply a reverse tone curve, and some of the tools work backwards, but it doesn’t take long to figure it out and when you see a slider does the opposite of what you expect you just move it the other way. I haven’t found it to be a big deal.
I haven’t digitized many color negs, and most of those have processed reasonably well by just reversing the curve, getting a neutral gray from the film border and fine tuning with the white balance sliders. Getting it exactly right needs a bit more fiddling. Once you have a good profile it can be applied to other frames in the same film.
I am glad, however, that the bulk of my digitizing is with color transparencies and B&W negs, as they are easier to work with.