All generalizations are dangerous and a boat being beamy and with the beam pulled back is only one of the many elements in a boat design "composition" but I can tell you for sure that the reason why the Open solo race boats are beamy and have big transom is not to have more interior room
and also that those boats are not designed for inshore racing but to deep offshore racing.
The reason because modern cruisers are based more and more on open boats has to do with the fact that this is the hull shape that if well designed can provide more easy boats to sail (that's why it used for solo racers) specially downwind. It provides also for powerful boats and therefore fast boats. They are optimized for downwind sailing being the weakest point upwind sailing with waves, a thing that most cruisers don't do
Regarding bluewater sailing, if you want to travel the wrong side, against the winds, this type of hull is far from indicated but if you want to travel along the trade winds (that is what almost all do) then this is the kind of hull that if well designed make it easier, namely in what regards using autopilot.
No doubt about that: the extremely wide and aft beam of the Pogo gives excellent control downwind, especially in waves.
Much better than e.g. the IOR typed Dehler 39 we sailed extensively before (less beam positioned much more forward, narrow transom).
I fully agree with Paulo that this firstly has to do with the enormous form stability of the Pogo, very efficient to prevent rolling.
The Dehler was quite a roller and rolling movements cause a lateral imbalance between the center of effort (sail) and the center of resistance (hull), generating a rotating couple of forces that constantly must be compensated at the wheel. These rudder movements even reinforce this imbalance and that’s why inexperienced helmsmen can induce a broach or a gybe by overcompensating at the wheel.
I also agree the twin rudders are less important downwind but essential upwind, because when heeled even a very deep single rudder would soon be lifted out of the water.
If the boat is also sufficiently light to be able to surf down the waves, you sail at around the same speed so the transom doesn’t get hit by the waves and you and encounter much less waves which makes it easier and more comfortable. In good conditions (especially long, oceanic waves) you can even overtake them
Of course all this comes with a price: less pointing ability and an uncomfortable behavior sailing upwind against seas, because of the lack of inertia and wave drag (I can’t find back your excellent earlier post about this, Paulo
But of course “gentlemen do not sail upwind”…