This is my amateur take on this:

Pretty much for this type of racing you want to be behind, you force your opponent out front and stick to their wheel and force 'em to set the pace. The trackstanding and fakery are just extreme examples of forcing your opponent out front.

Also forcing you oppontent inside means you're up track of them and you can use the banking to really launch you on your attack.

If they're out front, you have the advantage that you can see what yer opponent is up to, but he can't see you. That way you have the surprise for attacking. The drawback is that you'll have to go around the outside.

That trackstanding video is nuts. I'd have given up and just got on with it