These particular unique buildings bother me. All unique buildings (and units) should have different abilities so that you can't immediately judge which is better but these buildings are very similar.
Argentina's Supermarket grants: +20% gold with resources from their core area. +10% with other resources. Loses health bonus from deer.
Brazil's Grocer grants: +25% gold and an extra health with resources from their core area.
Colombia's grocer grants: +25% gold and an extra health with resources from their core area.
Congo's market grants: +10% gold with resources from their core area. +20% gold from other resources.
Mali's Forge grants: +10% gold.
England's Bank grants: +15% gold.
Poland's courthouse grants: +10% gold and +2 happiness
Which means that the buildings clearly (almost) go in order of power. Mali, Poland, England, Congo, Argentina, Brazil, Colombia.
There are differences like Argentina, Brazil and Colombia come later so they should get more powerful buildings. But you shouldn't be able to compare them to other buildings and instantly judge which is better.
So in this regard Poland is not in this category because it has another ability which makes it harder to judge its worth. e.g. is +5% gold better than +2 happiness.
What I'm saying is that the buildings should get different effects. (I have no ideas though)