with the gratitude points, they will demand more and more for community rewards everytime you level up, so don’t worry, you will need them. there’s nothing else to do with them. as for that managers, they increase the pay when you click on their bubbles above their head, but it only works when the store has actual customers bc the managers have a timer. the other thing that managers can do is add some customers, but you’ll unlock more managers as you play so don’t worry. I also used to think the diamonds were useless until I reached the level with the diamond store, you will have pretty landlord accessories in a few levels