"Scooping"(one way of bending a note is how I'd describe it) ,much like "runs"(melismatic/ornamental passages like Leona/Mariah tend to use a lot of) can add to the delivery of a vocal IF done with taste ,understanding,and control within the context of the song as a whole,and with genuine "feel" for why you are doing it. I am a full dramatic with coloratura ext(Can effortlessly sing Queen of The Night aria or Whitney song by same name lol)but went the jazz/soul /melodic rock path because I had the voice but not the passion for classical,so went with my instincts.
I think that's why I can appreciate Janet going with hers. I may not like the sound,but can see/understand the appeal .It is easy to tell when Janet is or isn't "feeling" the song she is performing. On the show,this can be a weakness,but in general,it is not,because ,with a song she feels,people are drawn into her performance.Even me,not liking her tone/style much of the time.That is a gift she has.
As for picking apart voices,someone mentioned why single out only Janet? (Though of course,you're entitled to your opinion,bless your vocally trained little heart and aparently pert bottom,O.P.

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I agree.Frankie and Kitty are much worse.
Kitty was born with that shrill,nasal tone that most here who studied voice will know there is no "cure" for.Even with training,she'd be Ga Ga lite.She can shout in tune,though she tends to flarp a lot of shat notes,

but no matter what she does,she will always be a mediocre singer who can passably manage pop and rock tunes as long as they are simple with melody lines that hover close to middle-C.Good tribute act,but vocally she's karaoke,
I won't even go into Frankies,um,voice,because I think we can all agree that,if any of them "can't sing" it's probably him.He technically "can",just not well,and preferably never into any form of amplification ever ever ever EVER again