You are right in that interviewers will grill you on them. I think it is because it is complex enough that it will show that you actually know what is happening and not just sound like you know what is happening. It is also simple enough that they can give a cheatsheet to the interviewer with the correct answers as there is only one correct answer for questions regarding b-trees, unlike most other things where there are 10,000 different ways to do something.....
Why am I getting lectured about Final Fantasy? Eat shit how about that.