I brake with my left foot, but I wouldn’t exactly recommend it for all drivers. I guess it depends on style. I drive an automatic, but I always switch it over to manual and use the paddle shifters. Left foot braking can be helpful though if you need to stop quickly, since you don’t need to transition your right foot from the gas to the brake. It can help you stop 70ft sooner braking with left than if you did with right. However, it can be VERY uncomfortable just holding your left foot over the brake all the time and you may accidently brake when holding the left foot over the brake.
If you really want to brake with the left foot, I’d only use it in high traffic areas where you need to brake a lot, like in traffic jams and roads with many turns. No reason holding your left foot mindlessly while on the highway.
Left foot braking is mainly for the race track, but you can use in regular driving as well if you want, just do it if your comfortable.