Customers or Staff? Who is more important???

I have been to the store on more than one occasion, usually just before closing, to purchase a few items. I am a smoker so I frequently visit the kiosk (since I am not selfish, I don't expect your cashiers to abandon their tills to fetch me cigarettes from the kiosk, and in the process, hold up the queue.) I find it totally unacceptable that every time there is a queue of staff members using the kiosk till to purchase groceries. Now my question is, who is more important? Your staff or your customer? I find it absolutely absurd that I have to wait for 10+ mins for your staff to be served before me. (It takes longer sometimes as the employee and the cashier first have to strike up a conversation) You can surely serve them after the store has closed and all customers have left. I am not the only customer inconvenienced by this. If this continues, your store will never see me again.....