First of all, Hawaii probably would not want that in spite of the financial benefit. They do rely on players from the mainland and their recruiting would suffer not having games here.
But it's an interesting idea, and the extra games would be a huge bonus for the entire conference. Maybe an arrangement where they played 6 home conference games annually would be more workable.
I would guess their ticket sales would increase being in a conference with more engaged fans. Who wouldn't love a trip to Honolulu every couple of years to see a BYU football game?