they do have a point, however, I am not sure how valid it is.

it is a safety feature that if one end blows out you will still have some partial brakes.

I have owned 3 cars with single pot masters.

1st car, single pot manual, I drove into a wall. But I was young and didn't know I had to check the level due to wear. So I ran the master cylinder empty.
would probably have been saved having a dual pot, just because both would not have worn as much that both would be empty.

2nd car I was a better driver. single pot but power drums.
Got on the emergency brake after the failure.
the rear drum lost a spring and blew out the wheel cylinder.
I was able to limp it home using the emergency brake through traffic.

Same car, somewhere on the way across country, the rear drum blew out again. ground down the star wheel and everything. honestly don't remember how, but I made it several hundred miles on that with only one side of the emergency brake working.

didn't need it, but could have been helpful in both cases having a dual pot master.


3rd car I switched shortly after getting it home, but only because I wanted power brakes.