Is it entirely worthless to build a Customs House on a map with only 1 landmass?

Is it similarly worthless to build the Forbidden Palace if you're already running State Property?

Is it entirely worthless to build a Customs House on a map with only 1 landmass?

I've seen conflicting statements on this. Based on how it normally works it should be pointless, but it may work differently on a Pangaea map.

Is it similarly worthless to build the Forbidden Palace if you're already running State Property?

Yes. If you're going to stick with State Property the Forbidden Palace (and Versailles as well) is useless.

Yes. If you're going to stick with State Property the Forbidden Palace (and Versailles as well) is useless.
Not entirely worthless, there are always the GP points and culture, and Versailles has the denial value.

Not entirely worthless, there are always the GP points and culture, and Versailles has the denial value.

To add to say1988's point,

If one wants to ever use a corporation, one will have to forgo State Property in lieu of the corporation.

Prior discussions have proven that the description for the custom's house is incorrect. The custom's house affects foreign trade routes regardless of whether they cross water or not. Guess is that the behavior was modified but the coastal/harbor restrictions remained.