as the saying goes.
It really doesn't matter. A blur is a blur.
I see blurred eyes and I think they're too close together or she has an odd forehead.
Blur your mouth and I imagine snaggle-tooth or a weak chin.

At least that's my $.02 worth.

Smile for me baby 😊!

Not a hit on this post but most companies or people who want to sell a product want to picture it in the best possible light. If blurring is a must , less is best .  

http://www.harpersbazaar.com/beauty/makeup/a11934/eyebrows-are-most-important-facial-feature/ Science Says This Is Your Most Important Facial Feature ... And it's not your eyes.
... [eyeBROWS are #1]
.
http://pubmed.ncbi.nlm.nih.gov/30218914/
Critical features for face recognition
.
"... We found a subset of features for which humans have high perceptual sensitivity to detect differences between different identities (high-PS features). We then showed that systematically changing high-PS features changes the identity of faces, whereas changing features for which humans have low perceptual sensitivity (low-PS features) did not change the identity of faces ..."
.
High-PS: 1. hair color, 2. eyebrow thickness, 3. eyes, 4. lips
Low-PS: 1. skin color, 2. face proportions, 3. nose, 4. mouth
.
I think QB should conduct an actual study looking at the effect of BLURRING (compared with covering with a decoration, splotching, pixelating, ... etc.). Maybe collaborate with someone here:  
http://psychology.ucsd.edu/people/faculty.html  
and search "perception"

I would blurr my eyes for discretionary reasons.  Eyes are more revealing  than  the mouth,

I saw a twitter thread with Canadian girls who got stopped and questioned at the US border when entering based on facial recognition from LeoList adsSome were denied entry altogether while others where just questioned and let through.  I was surprised how many women chimed in on the thread stating that it happened to them too.  Weird but another reason why many women don't show their face in photos.

Please don't blur. Use something to cover eyes, mouth/nose, or whatever you want hidden. Blurring distorts the part of the face that shows. It happens whether you want it to or not. Use a black bar across the mouth. Better yet use a mask, wear a hat brim pulled down, use a fan, get creative with things that go with your outfit, something that goes with you photo theme.