Say that after doing Arena or Colosseum.
Expeditions seem like they can be pretty rewarding. Not super involved, but maxing out your % while fitting in bonus units is sorta fun. At the very least, it's likely at least an extra 100 Lapis and summoning ticket a week, 4* moogle if you can get that high too. Guess we'll need to wait and see for a week or so and see what sorta rewards people are getting.
They also added push notifications you can turn on for everything in the menu. Energy, raid orbs, arena orbs, and expeditions are all listed.