Love em! On my final set of an exercise I love to finish with stretch position partials. It's shown to be beneficial for hypertrophy due to:
1. Extended tension time
2. Blood flow occlusion
3. Stretch position overload
If you do it right you should not be able to do another set of that particular exercise. Works amazing for barbel curls, leg extensions, tricep exercises on cable, almost al cable exercises.
Only exception is MC IGF, I'm having hard time burning out my muscles as I recover even after most taxing sets fairly quickly and need to do a lot more volume to fatigue them muscles like before. I guess it's a good thing! Lol