He won't be doing much thinking if he's covered in PR obligations for the live action.
Also, last time he did take time off to think about how to properly approach the story, he then gave us Bonney fainting to bugs and screaming at Vegapunk while assposing. So not exactly the greatest track record.
When you do a longer hiatus it takes off a lot of pressure.
If he doesn't take it, he has to do PR appearances etc. anyway - all while drawing the manga, too.
Now he can just relax a bit, do some other stuff, think a bit about the story and then come back fresh and motivated.
Btw that argument about 2 or 3 chapters after the last break is hilarious: Not only were those good and much needed build-up chapters, it's also not like Oda only plans out a few chapters during the break. It's much more important to create a bigger overall writing plan, which he obviously did if you look back at the entire year.