I agree about Markets... Even I build them only in biggest cities... And I play Huge/18 civs no-tech trading games last 4-5 months where time lines for everything are much later so also longer time to pay back any investment (can't base all game on few bulbs and tech trading
if I need something, I must get it by myself).
Still if can get 2 OR+Forge whips with max overflow and has atleast 2 of 4 Market resources... it will pay back pretty fast and Wealth won't be better
if I need something, I must get it by myself).Still if can get 2 OR+Forge whips with max overflow and has atleast 2 of 4 Market resources... it will pay back pretty fast and Wealth won't be better

for any Civ. This bonus is generated even if that Civ is not running a State Religion."
again
, they create extra gold
(the icon is very similar and easy to confuse). If you convert commerce to gold via the slider then yes markets are useful and are producing extra gold for your empire.