I used to think this way, but listen to this, i just recently went on a rampage and completed chapters 12-13-14 all in a hurry, dumping portal profit one after the other, without bothering much with the settlements as those chapters allow us to circumvent the process if we wish to.
Now, my performance in tourney, using pretty much the same tools went up.
my relevant AW's didnt change much (like the + attacks or MM). I would place 1-1-1-1 every week, as before and feed the bird, as before.
But now, the difference is, i make so many resources of every kind, and my military buildings can crank a LOT more troops
And thus, advancing made my game easier, and i've bumped my tourney performance by at least 25-30%. From doing maps 1-10 to 6* and maps 11-24 to 2*, Now i can do maps 1-24 to 6* no problem and some weeks i even push it to 30 provinces
There is no way a chapter 8 town can pull that off
I should note that between end of ch.11 and beginning of ch.15 i must have added about 20 expansions, some premiums, some research, some world map. My performance is much bettter, as i have more space to put everything i need
You should remember that advancing research eventually allows you to upgrade all your units to 3 stars (and now, some at 4 with the last chapter), and THAT is what you advance for
I will agree with you however on what you say, but only in the case that you have diamond farming towns. I suspect you want to spend as little time as possible in those, and so in these cases, as i do myself with my own 7 subs, growing them becomes too much trouble