The points attributed to the first rounders help us get our academy kids easier. Unless we managed to get 2 more picks inside the top 10, and a pick high enough for Weitering, I dare say we wouldn't go "external" in the draft.
That is what your not understanding, with this whole 2 x 1st rounders thing.
Hopper is rated around pick 5 and Kennedy around pick 10.
Let's say AT chooses Collingwood and we offer up our 1st and 2nd round picks. That's pick 7(after this weekend with GWS and Port wins) and a pick around 26. Will get pushed back some with the academy and compo picks.
Pick 7 gets you Hopper because of the academy player discount from a pick 5 bid.
GWS use their own pick 8 or 9 for another talented kid.
GWS use our pick 26ish and their own 2nd rounder, pick 27ish to secure Kennedy from a pick 10 bid.
GWS have 3 top end talents and finish at the draft. Shallow draft and no need for later picks who'll clog your list.
Now, if you get 2 x 1st rounders in the teens.
GWS use their pick 8 or 9 to secure Hopper.
GWS use their trading in teen pick for Kennedy.
GWS are left with another teens pick to use. This pick is likely to have been pushed back due to Mills, Hopper, Kennedy and Keays all rated in the top 15. Hip wood might force it back further.
GWS are unlikely to use their 2nd rounder when their list is already quite full with talent.
So you're basically tossing up between a top 10 pick (if trade in picks 7 & 26ish) or a high teens pick ( if trade in picks 13 & 15). The 1st scenario throws up better because you are utilising your 2nd round pick to maximise your position. It'll be wasted otherwise because your academy picks will already be done.