I've taught a lot of non english speakers how to shoot over the years. Sometimes they get a lot of training and sometimes they only get what I give them for years and years. A fair number of them have been in gunfights over the years and I've heard back from some of them, though not always in enough detail to be really useful. I always taught eye level sighted fire for the majority of the class (1 day to 1 week, usually), however, I always include a very short session on target focused shooting. Very close ranges, and very high speeds. I don't know for sure if it matters, but it doesn't seem to hurt. After a day of sighted fire, target focus can be taught in a matter of minutes. I really believe it can't hurt and it could help. They do seem to have fewer trigger issues when using a target focus at high speed. Of course, I always emphasize that the gun should be brought up to eye level and pushed out just like it is when using the sights.
It takes a lot of practice to do a press out at high speed with high accuracy. Less practice but almost the same results (with more speed) with the target focus at close distances.