Try it, no harm in an extra swatch, wash cloth or scarf is there?
I wouldn’t like it myself. I already get too much of my hair knitted into my sweaters and that’s with regular vacuuming, if I had yarn around my neck I’d end up with the sweater attached to my head and all my hair purly instead of curly!
Also, I do make very similar movements with my left thumb when I do colour work as I have one colour in my left hand and one in my right, so my left hand works the yarn continental style (which I learned for the purpose of colour work, also there seems to be a big push online to make all knitters change to continental which I disagree with but thought I’d try it out) and I tend to work flat so my left thumb is knitting and purling with that second colour. It’s fine and I get a reasonable result but I definitely i would not want my left thumb doing all the work I would find it too painful.
I’ve noticed you’ve mentioned being unhappy with speed or style a few times so it obviously bothering you.
Where I’m from people who have been taught to knit by a family member very often use a style that is not often see online in tutorials. I’ve seen expert knitters question films and cartoons which portray a character knitting this way as it is apparently impossible and not how anyone knits. But actually rather a lot of people knit this way.
It’s similar to flicking, yarn in right hand, but the right needle sits on top of the hand, a bit like a pencil, rather than under the hand like a dinner knife. There are not many available tutorials on this they are quite hard to come by but a range (all variations on a similar style) of information can be found by looking for Irish cottage knitting, parlour knitting, pencil style knitting, and it’s like a variation of lever knitting or knitting with a knitting belt but no belt is used and the right needle doesn’t have to be anchored under the arm.
I wouldn’t be able to find exactly how it is but this is similar, stephanie pearl mcphee (one of the fastest knitters) who is known for fast lever knitting but in this video is using DPNs so the needle is not anchored. This is very similar to how I knit but my yarn is tensioned differently
In looking for info, and not really finding it, I did find a series of knitting kits and lessons for sale which seem to be promoting themselves as having a ‘new’ technique called The Knitting Pretty method. It’s not new, I’ve just watched an old TV news report on a knitter who has been knitting over 100 years and she uses the same method in the brief clips of her knitting in action, and she was taught by her mum, who was probably taught by her mum, who… anyway… some of the earliest films of knitters how they hold needles this way, it’s old old old.
In this promotion video you can see the style in action in the first couple of minutes. She also tensions in the same way I used to tension which cramps up the little finger, it’s how I was taught when I was a kid. When I started knitting regularly and joined this forum 4 years ago I discovered after a while that I was getting cramping in my little finger from this method so I changed how I tension my yarn, little finger is no longer used at all but otherwise this is very similar.
I’m not suggesting this is the best way to knit, not at all, I believe the best way is whatever you are happy and comfortable with, but having seen that you are primarily and English style knitter, but not very happy with your current style, I thought I’d offer an alternative which is similar, but different, and which is not at all easy to find in tutorials. But it might suit you.
I’m not a speed knitter but I can knit pretty fast this way. There is almost no difference between knits and purls the action is the same so no stuttering in the preparation of moving yarn forward. The forward movement for purl prep is almost identical to performing a knit stitch, then the purl itself is almost identical to performing a knit stitch, and the post-purl movement to bring yarn in back again, is again pretty much identical movement. It makes for a comfortable and rhythmic knit .
What I can’t do is small circumference knitting in the round on circular needles, the angle of the needles is all wrong for me, I’ve come to the conclusion I would be happier with DPNs for small circumference, as Stephanie gets a decent angle on hers in that video, but I have not been motivated to buy DPNs or try it out, mainly because I’m not interested in socks, and I rather like flat knitting sweaters and seaming them.
Well, I hope you find a style you like, if that is Portuguese, or parlour, or any other.
Of course I’m also a AAA class klutz. 
