Is black plate worth it?

[Sombre]

In what sense do you get 1.4 smiths? That's a gross oversimplification. You haven't even shown that you get more gold or castles by building black plate over chainmail after the first couple of turns. You say you save gold, but you admit they aren't as good for quick expansion. I could argue that quick expansion nets more gold, which means more castles and smiths, therefore I have 1.4 (Since we're going to apply this figure to everything apparently) smiths to your one and it would make just as much sense as what you're saying.

[Baalz]

Well, if I spend 2000 gold on infantry and you spend 2800 then I can afford 5-6 more smiths or an extra castle. 40% more troops is not going to equate to 40% more expansion of your map move 1, more fragile troops, and most certainly not 40% more staying power when you start fighting tougher foes. This is compounded by the lower upkeep cost if I'm buying castles as I suggested.

Look, I'm not saying there aren't situations where the chainmail is useful, and you can certainly use them effectively. I'm just answering the original question as to if black plate infantry is worth it. I think so in many situations.