They have the power of making coffee, obviously, you idiot. But their actual powers come in the way they deal with customers. and go about their day
The barista becomes IRATE when a flood of customers comes in or someone comes in and obviously doesn't know anything about espresso
When a barista is swamped with orders, they invoke incredible Time POWERS and become enveloped in a slower time field, effectively doubling the amount of time it takes them to make coffee.
Unlimit Caffeine Overdose
The barista can drink an unlimited amount of coffee without experiencing caffeine toxicity. The drinks must be free and obtained during their shift