How do you use the rewards in the cafe, such as competition hint, new drinks, new portrait, etc?

In the lounge café, tap on the shopping bag icon in the lower left corner to enter the tips store, where you can by the following:

Competition hints can be bought singly or in a pack of 5 for convenience of purchase. Each hint can be used for a single hint during Time Rush and Spot the Difference competitions. The advantage is you will not lose time during competition, which may help your score.

Energy upgrades will increase the value of your drink every time you serve and when others accept your drink. Upgrades can only be bought one at a time.

9 to 10 = 10 tips

10 to 11 = 500 tips

11 to 12 = 1,400 tips

12 to 13 = 3,600 tips

13 to 14 = 6,600 tips

14 to 15 = 12,200 tips

This is the best way to help your team.

Pink 5-star boxes can be purchased one at a time for yourself and have the same content and odds as the ones earned when a hidden object scene is "mastered".

Fancy drinks can be purchased for cosmetic appearance only. They do not have any game advantage and provide the same energy as your coffee.

Avatar portraits can be purchased to change your profile picture and do not have any game advantage. Once purchased, look for them in your list of avatars by tapping on your profile picture and then the pencil next to your picture. Unless you specify otherwise, FB friends will continue to see your FB profile instead.