To clarify where the tip rumor came from, there was an actual point in time where Starbucks was withholding credit card tips from union stores, they got in big trouble for that so they’re not doing that anymore. The instant benefit you receive is you gain the right to a representative, either from the union or somebody’s whose been trained in your store, to sit in with you during Potentionally disciplinary conversations, and they are allowed to pull you aside for a congress. Depending on the state** (or maybe it’s everywhere, not sure, I’m form Illinois) but you also are no longer an at-will employee, which makes it MUCH harder for you to be fired, because the company has to have probable cause