The first question is possible if it's a phone conversation: "Where are you? Have you gone to the bank?" This basically means "You're not here, but I think you may be at the bank, or on your way there."
"Have you been to the bank?" may be asking why the listener has money now, or where they were a short while ago, or if a bank errand has been completed.
Don't feel confused. This is simply using a past action to explain a current situation.