Or was the manager just interested in trivia?
Don't get discouraged. Work on a personal project if you want, so you have something to show. In my experience it's only hard to land the first job. Once you do, it becomes easier. Don't read other people's experiences and think something is wrong. Good luck <3
I've also interviewed at Two Sigma where I was flown in onsite and by the last interview they had already reviewed most of my feedback and told me that they were going to extend an offer. I got the sense that if I wasn't using a 3rd party recruiter with rules they might have handed me an offer before I left offsite. But it was great having the chance to talk to my would-be manager knowing I would likely have the offer to discuss my role while I was still onsite.
No hard feelings on my end; I was out of my depth at the time, and knew it, and was glad I wasn't going to have to waste the rest of my day and theirs.
If, during an interview, it becomes obvious to you that you aren't a good fit at the place for whatever reason, you don't have to wait for them to end the process early.
Doing so yourself is not only acceptable, it's also a professional courtesy that they will appreciate.
Remember, with all interview processes, you're evaluating the potential employer just as much as they're evaluating you.
Given how the other processes work, I sort of prefer to get it over with. But I understand that that's not viable for people searching while still working full time.