Thanks. I must say I find it rather confusing when they make all these status miles, cabin bonus, etc...

If I read this correctly, I will get:

Base miles + cabin bonus

(But no status bonus, therefore, to move up to gold, this trip isn't going to help me one bit...?)

I think I'm still slightly confused between status miles versus status credits. I've read the T&C a few times, but I still don't think I understand it properly. As I understand it, you get 1 status credit for every 120 status miles. For x status miles, you get upgraded to the next status. For the purpose of this exercise, since my flights aren't QF or AA, I won't get any status miles...?

The QF points calculator doesn't really help because it only has QF flights, it doesn't do other OW flights.

What are the reasons for airlines to invent all these different type of miles?

The only good reason I can think of is to minimise the majority of QF members (i.e., bronze) to move up the ladder, but reward those who fly quite often anyway.