Well, I don't think interviews are always about answering something correctly. It might just be nice to have an applicant's opinion on x y and z, to spark conversation, gain some insight into their personality and what is important to them, etc. In my opinion, discussions like that can be invaluable: sure, someone might have all the technical answers correct, and if so that is great. But humans are more complex than just being right or wrong. It's also good to see if the candidate has a similar view on the role they would be fulfilling.