Except when you've made it your goal to hit mathematics and enhance as quickly as possible. In that case monuments in your secondary cities do nothing whereas a council in your 2nd and 3rd city might shave a few turns off your research time. I'm not necessarily saying it's the strongest way to play the Maya (though that would be a fun debate!) but I've made it my goal to try to exploit their UA as much as possible and with that in mind those councils are helpful. I totally agree that monuments are more important than councils in pretty much any other situation I can think of. Except maybe if you go ancestor worship possibly?