You are wagering a lot on your reflexes. While your life & safety are yours to wager it appears imprudent advice to offer to persons unknown. The downside risk for guessing wrong is horrendous and it’s hard to aim & fire in split seconds. I did not get the impression your advice was predicated on having a gun either.
That being said, your method is what I had used in the past to defuse situations with unknown dogs. That was before the many reports of people being killed by other people’s pets. Now I am more wary.
I did say that it may not be the best advice. It’s worked for me may not work for everyone or every dog. And I’ don’t wager my life or anyone else. Sounds like you like to blow your tune a bit. I would not try my method with a frothing mouthed rottweiler. I was speaking as someone how has had some experience with dogs charging towards me and unarmed. I have also had to run into my truck on a few occasions, but never killed a dog.