Partial reps in the stretch position is the new fad.
Studies have shown it is great for hypertrophy.
This is not a new idea though.
I think there's something to the idea. I will also do an extra set with partials in the stretched position from now on. But at the same time there are reasons where you might want to do some exercises without any fully stretched loading. Obviously you can grow without any full ranges of motions at all. That Nick Trigili said you only do the bottom range of motion you aren't growing your pecs. Of course you are, you are training in the probably most beneficial range.
I always did partial stretched positions in the squat. One full, one or two short, then a full again for example.