Newbie Question: Culture Modifiers

[Purna]

So, for example, you would pick engineer if you wanted to exceed the repair cap of 150? Even getting to repair 150 with the same bonuses and penalties as an engineer only costs 2925 racial points when applied "by hand," whereas it costs the engineer 3000 to get to repair 145. Is it really fruitful to go above repair 150, or is engineer not commonly played?

Of the unmodified cultures, which are generally considered superior? Is it simply a matter of total racial point costs/bonuses, or is it deeper than that?

Solely based on racial point costs/bonuses, I get the following ordering:

+525 Berserker
+525 Warrior
+375 Worker
+350 Zealot
+250 Artisan
+125 Scientist
+125 Schemer
+125 Trader
+75 Politician
0 Neutral
0 Renegade
-50 Merchant
-125 Xenophobe
-450 Engineer

(I am assuming that Space Combat culture modifiers apply to both attack and defense.)

I know that some traits are more important than others, but except for going outside the normal allowed ranges, it seems that you can just pick a high point-bonus culture and "undo" the cultural modifiers to start with.

Maybe you don't think productivity is important. You could still pick Worker, for a +5% productivity bonus, and then set mining/farming/refining aptitude to 95. You're back to a "neutral" culture, but you have 375 extra points to spend on whatever it is that you do consider important!

So, what am I missing? Do people pick a culture solely so they can exceed the normal attribute caps, or do they just choose the ones worth a lot of bonus racial points?