Because it´ll take time before the marines send (if at all) the admirals for him and then it´ll take some time for them to actually get to Dressrosa. In the meantime, he´ll deal with the whole Law transaction situation.
What felt weird was the fact that Law said today that he was going to give CC back to Dofla now…we know he wants to lower the strength of Kaidou by making sure no more SMILEs were produced:
- by destroying the factory on Dressrosa (last chapter)
- by having Dofla quit the Shichi so that he´s hunted by the Admirals and can´t produce "safely" on his island (Dressrosa),
but why doesn´t Law simply kill CC is beyond my understanding. That´s the only foolproof way (as Dofla said).
He wants to break him down bit by bit so then he'll be more vulnerable… it's like Doflamingo is a lemon, and he's using the hand, Caesar, to squeeze as much out of him as possible.