Why would I be asked at an interview, "What you you say if we offer you the job?"?

If you want the job you say "yes" .

If you answered anything other than that, you may want to keep looking for jobs.

Why they asked it was to see if you think quickly. A quick thinker would have said 'YES'...because a person who did not want the job would have excused themselves and thanked the interviewer and said 'this is not a good fit, but thank you for your time."

So if you stood there and mumbled or looked confused....if you said anything but some version of 'yes'. keep up the job search.

I wish you would stop posting so many goddamn STUPID questions every damn day.

I would start dancing

They're trying to determine if you're someone who has already made up their mind about wanting that job and wanting to work there, versus someone who is testing the waters and may have other jobs on the line.

To see how enthusiastic you are.

The response would be I would be honored to accept it.