What are one-on-one’s actually about?

I usually get a one-on-one every two weeks and the conversations are mostly pleasant with me and my manager.. but what exactly is the point of a one-on-one? Are they for planning out your personal goals with your manager? Are they there to keep you in check and make sure you’re doing work? Do you just socialize and have a beer with your manager? Again they are usually pleasant but feel awkward because I’m not 100% sure what they are for.

Thought I’d ask this sub and see if you guys knew what the purpose of one-on-ones are.