I have a scenario. It's the last couple of laps on a fast bumpy track and I am hanging. My forearms look like Popeye's I dont think I would like to rely on having to grab a hand full of brake in my weakened state.
A foot brake would all ways be safer in my opinion
One of the reasons I bought my recluse clutch is because in tight trails, trying to use the clutch and the front brake wears your arms out. Also on the track having to grab the clutch so I wouldn't kill the engine coming into a corner would get tiring as well. Some people say not using the clutch out of corners means you are going slow but if JS7 can do it, I go much slower so it is ok for me too.
Even on a bicycle, I preferred the bicycle that you would turn the pedals backwards to engage the brake seemed more natural to me.
I do agree the foot brake on a dirt bike makes right turns more difficult but so does pulling in the clutch or both hands off the grips to engage both brakes when they are both on the handlebars.
For me anytime my hands are griping the grips and not letting go having to reach for a brake or a clutch is a good thing for me.
In the end it is what you are most comfortable with, I think your brain can adjust to any situation, but if you start out as a child doing something, that will be the most comfortable thing for you to do.
The question is which is more optimal. That is difficult to judge