Works like the scout post and such. Activate buff before starting adventure and all adventures started while active gets special buff that increases the chance of the rarer loot drops. Take for example a Woodcutter adv. You have a low chance of getting 2000 beans or 400 grout and a higher chance of getting 1500 beans or 200 grout. With this buff active the chances of getting the higher returns would increase meaning better loot with the buff. This buff would also increase the chance of building drops and follow-ups slightly as well. (making getting the needed maps for weeklies and side quests a little easier) It would also help with events as it would make getting the higher event drop a little more reliable. And since it is only two hours duration every couple days (depending on how many you are allowed to have) it doesn't break the game at all.