Those don't necessarily have to be different goals, do they?

Everyone who fought in the dungeon that girl created got more fighting experience. Rei herself is happy and fulfilled, which means her ability to work with her Persona is improved and she can join us properly in fights again. Plus, everyone gets a little break to be happy and celebrate their success.

No one can keep fighting forever. If you don't stop to rest sometimes, you get tired and discouraged.

One day of festivities won't stop you from being able to return home.