Adventuring in bonus regions allows you to receive substantially more EXP and Gil, as well as fusion-specific cactuar cards.
However, note that each incursion into a bonus region has a time limit. Once the time limit is reached, the region is once again locked to you, unless you use more Mystic Tablets to enter it once more.
Bonus region reset[edit | edit source]
Select the bonus region from the world map and tap Reset to attempt the region again.
Mystic tablets will be spent upon reattempting the region.