Not really that strange. Nothing magic about air brakes. Either hydraulic pressure or air pressure can be used to actuate the brakes. Air brakes are heavily used in the trucking industry because it is much easier to connect tractor and trailer by hooking up an air hose than by connecting and then bleeding hydraulic lines. This carried over to many motorhomes because it was easy to spec truck components. That does NOT make them better.
Our 2003 Alpine has 4 wheel disk brakes with ABS. Calipers are fixed with 4 pistons. Boost is hydraulic over hydraulic-- better than our 4 wheel air drum brake coach.
I have driven coaches with both-- pedal feel is much better with hydraulic and stopping distances are excellent.
So, in many respects, air brakes are good, but are more a "buzz word" than actually superior.
BTW, don't Boeing 747 at over 1,000,000 pounds use hydraulic brakes???
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240