Alright, but then how do we get a grip on the overall superiority of cash heavy players?
If we can't defeat their armies etc.
But cash/diamonds won't have any effect on armies when you take a battle singularly. If you're at the same part of the tech tree (which is obviously limited and based primarily around hourly knowledge points for progress) then you can have the same unit types and squad sizes. Yes someone who has spent cash can have more supply income and space for armories to rebuild armies quicker, but that just means they can attack more people per day. Defending will only need 1 max army.
And can you tell me if Goddess of Fertily adds to player score or not?
They have the same grid size as a Lvl15 Residence and also add 420 pop
Do they generate coins as well?
Yeah if they give population then it'll give points. But it's not that much overall. Like I said at the start, diamonds will give more points through 15 expansions and better buildings, but it's still limited. If you had unlimited diamonds there's still only so much space that can be filled by so many buildings. Unlike with FoE, you got loads of points just from collecting coins/supplies and so if you spent real cash then you'd get a higher income rate to get more points every day, as well as one off points from the diamond buildings.
And why would you care about culture bonus once you have everything upgraded, scouted and research tree is done too?
Isn't it about maximising player score once you're done with everything else?
2 parts to this.
Firstly, as diamond cultural buildings give better culture per square, you could buy the best buildings and get whatever culture bonus you wanted with less space than with non-diamond buildings - thus leaving more space for other buildings which generate points (as well as any goods, supplies, coins etc).
Secondly, once everything is researched and upgraded, you may want a 150% culture bonus for example, in order to get more coins/supplies allowing you to produce armies and manufacture goods quicker, which will speed up both fighting and negotiating more provinces. That's the only real end game right now, but I'm sure as Inno add more content in then there may well be more things to want to spend currencies on.