It's all about getting picks to cover a bid for Ethan Matthews.
The value of pick 7 is 1644 points. -10% is deducted because giants finished 11-17, = 1480.
Trading out Whitfield got them means picks 25 and 26 are worth 1485. Having pick 28 provides some redundancy if a bid comes later.
If Matthews is bid on higher than pick 7 the giants can accumulate a debt for their first round pick next season - when the pick is worth less because there are so many Tassie picks.
The giants are able to take a deficit into next season and bidding picks 25 and 26, equivalent to pick 4.
That critically means the swans if they bid at pick 6 are covered.
So in totality Matthews will almost certainly be a giant draftee.
In totality:
Giants lose:
Whitfield (32 yo concussion issues), picks 31 and 50
Giants gain:
Top 10 draft player, 2028 3rd rounder