I think they use ad buys like artillery to ‘soften up’ the battle space. He uses it in advance of an infantry attack. I hope. He uses Twitter for the softening up.
The point is that he held fire, didn’t get distracted by all the rope-a-dope moves to distract him and get him to spend himself into a corner 3 months ago.
Recall the media kept scratching their heads over his lack of spending. That was intentional on his part...
It’s called knowing how to fight and win in a complex battle space.