I had the occasion to ask the designer Stefan Dorra about this to get a clear ruling, and he confirmed that he prefer that the amounts of money are secret. So we'll keep the way the game is currently implemented on BGA, that conforms with the rules and the designer's preference.
Edit July 2020: further discussion has opened up the possibility, so this may actually happen.
Edit July 2020: further discussion has opened up the possibility, so this may actually happen.