It is a feature of the male voice and of the lower female voice where the harmonics are close enough to cluster the 3 upper formants, which constitute the singer's formant.
Pop singers suppress the singer's formant because it is not compatible with microphone technique and listening to the clip you provide here under acoustic analysis, the SF pops in occasionally for a brief moment and then is gone. And it never appears strongly enough to have the kind of dominant effect that it must in a classical voice.
If the comment is whether Whitney could have sung classically, the answer is yes with a bit of training! Looking at that clip acoustically, it seems much of her voice was prep for balanced phonation, if not for the microphone issue which is crucial to a pop singer's training.
Be not the slave of your own past. Plunge into the sublime seas, dive deep and swim far, so you shall come back with self-respect, with new power, with an advanced experience that shall explain and overlook the old.
Ralph Waldo Emerson