DSDP Don you have given us some good insight. I understand with motorized RV's the 1/2 bath allows for bathroom use with slides closed.
However with towables the extra bath does allow for easier access if there is a large group. However it adds an additional black tank that just creates more work if there is a small group that does not need the extra capacity.
The 5 of us can go a week on a 40 gallon black tank with ease. However if we use both toilets we end up with two half empty tanks vs. one 3/4 full tank. The tank cleaner (Me) ends up with more tank maintenance without gaining any real advantage.
I'm OK with a 2nd toilet. It is the 2nd black tank I have come to despise! LOL