this video was very interesting to me. I knit continental for 30 years, as I said. Various places of picking up ideas, techniques and help, but mostly just knitting by myself or teaching others.
So I was wondering....
my hand position for left hand is different than in that video as I wrap the yarn as I described above.
I do not have my yarn over the 3 fingers (and even before I wraped my own way, I learned to hold the yarn on the inside of my hand, running through my fist. So the result is that this method of purling in your video looks like something I have DONE before but do not favor.
My purling works by pushing the yarn towards me with my middle finger. I hold my knitting mostly with my ring finger and push the yarn forward. That seems to me as even more economical, since I keep my yarn finger (index finger) in the same position and do not tamper with the tension or the slack. I also do not have to dive the needle through that much.
I am just not near any of my knitting (lunch break) but I dare say: My purl is almost as economic as my knit. It IS a little slower but I dare say by a minimum fraction. Ribbing, seed and moss stitch and the like become no-brainers.
Nonetheless it was very interesting to me to see the video. I never tire to learn new ways. It also helps me when helping beginners and intermediate knitters, because I can help them on their way instead of twisting their brain.
And it will help me myself when my finger gets tired of pushing the yarn. I do not think that pushing that yarn endlessly in the same way is ergonomically good. Neither way.
So knowing this as a "different method" now, I can switch when I want to and that will be helpful.
No way looks better to me, just knowing them is good! Find your own style.