White could have captured g2 without any risk and attack the pieces on e4 and f3 at the same time, but… 1. i4-c2;xGc2 is more beautiful and makes him win the game with less moves. (If White would have played 1. h6-e6;x, Black would have been able to recuperate pieces at least one more time).
But now, since White removed his GIPF on c2, Black must play 1. … c2. The danger for White is that Black will go for d4. White can’t play h6-e6;x any more, so he puts a piece in defense: 2. h3. If Black would play 2. … d2 or c1-c3 (or even f2), he can reply with 3. i3-e3. By doing so, he brings a few black pieces together, but Black will not be able to get a sure capture in that area without putting his last GIPF in jeopardy. So, Black has at the most 3 pieces left to make sure of getting pieces from somewhere else back into his reserve, and, no matter how hard he will try, that isn’t possible with just few pieces in the right top corner.