I don't think the advantage of a dual master brake unit is essential. I believe the dual braking system was deemed a safety item when production methods and brake components were a lesser quality than today and were therfore more prone to failure. With a new brake system, stainless lined master, all new rubbers, stainless lined wheel cylinders etc, the chance of castrophic failure is very limited.
For example, heavy vehicles right up to the late 80"s had a single master and booster with a valve system proportioning the brakes front/rear.
Before changing to a duel master, I replace all components in the braking system on the car, in the case of my new project, it will also be upgraded with disc brakes front & rear.