The feature only works for group chats (because polling a two people is silly), and works just like you’d expect: type in a question and some possible responses.
There are a few obvious uses. Picking a restaurant comes to mind; I’ve had multiple birthday party groups in excess of 20 people. You could also present dates for a trip, ask for opinions on a particular topic, etc. People are also more likely to contribute their thoughts if they can just tap an option instead of writing a message out.
On another note, Facebook is introducing a ‘chat assist’ tool that uses machine learning to help you pay people back. Type in something like “could you send me the $37,000 bucks you owe me,” and messenger will prompt your friend to pay you back via its own payments feature.
While it adds a small does of convenience, it’s also a way for Facebook to onboard more users onto its payments system. I use Venmo for most transaction with friends and have no reason to change; I suspect many feel the same way. However, if a friend reminds me to pay something through Messenger and I’m immediately prompted, I might be more tempted to go with Facebook’s method instead.
The features are rolling out in the US, and Facebook could bring it to other countries depending on how they work out.