Oui,

It’s a way of talking to a person without initial using a command or some other request with inherent obligation or further action implied that could happen in public. What do I take off of my initial commitment to make a committment?

What should I be drinking? Let me buy you water. vs. “ahem, can I buy you a drink?

Are you a

good dancer? How do I Dance with Me?

What is the

premise behind having another drink? Should people have another drink?

This way a asker can assess the interaction and make a nice offer or become disinterested without having made the obligation already. The first part of asking Q&A takes pressure off the person asked the question. Which can be a very good answer?

However the goal is typically to buy them a drink, not so much to offer them but just imply that you will be doing it without the other person’s expressed acceptance.