Lol, after spending some time to make this post to explain why he did not want to attack with 9 but with 8, I've come to a conclusion that it was not even necessary (unless my calculation is wrong, but I don't think so). Well, I'm posting this anyway in order to explain why it was still better to what Mike did, and also to explain why Mike thought it was really great skill.
So here is my original post:
That's not for the extra delay. Attacking with 0 does not count as delay. The point of that move is that 1 extra army will stay in Argentina in the next turn, which will prevent Gnuffone from taking it in the coming turns. If Mike had attacked with 9, all 9 would have been killed (because 14 defending armies kill 10). And in the attack, 8 and 9 armies both kill 5. Now, here is why Mike is so inspired by that move:
Now it's 9 in Siple (Antarctica) and 3 in Argentina (again, if he attacked with 9 there would have been just 2 in Argentina). Since it's SR 0%, we can count if Gnuffone has a chance to take Argentina in the coming turns. Let's do it:
If Gnuffone attacks with everything, that's 19 armies against 15. It will become 9-4 at the end of the turn. In the next turn, Gnuffone attacks with 19 against 17 (notice that Mike will transfer 1 army to Argentina this turn). That will leave us with 7-6. As you can see, Gnuffone will not be able to take Argentina in that scenario.
Now, let's check what would have been if Mike had attacked with 9 on turn 7:
So, in turn 8 it'll be 19vs14. That leaves us with 9-3. Next turn it will be 19v16, leaving us with 8-5. next turn, 18vs17 ---> 6-6.
Well, seems to me that even if you did not make that attack only move, Argentina would stay yours. Am I mistaken? Maybe you forgot that you will transfer 1 army to Argentina?
That being said, I think turn 6 was nice :)
And I think Gnuffone could try playing a bit more, although there is a low chance that he can do something (he would need you to make a mistake, of course).
Idk though, because I might've made a larger blockade in Scand
He couldn't make a larger blockade. Look at turn 3, he needed exactly all armies to take CA+defend SA.