What would you say are examples of meaningful vs. pointless CS questions? Anecdotally speaking, I've heard of senior engineer interviews where the candidate has an impressive resume but has difficulty coding solutions to "basic" problems.
However, what meaningful questions will cover are advanced architectural problems, particular inner workings of a tool/framework, how to squeeze in the last few drops of optimization etc. Conversation should flow without any major breaks and the most experienced engineers will talk about edge cases of edge cases, thus continuing the conversation themselves. You can discuss different types of architectural patterns, ins and outs of each one and how it can be applied to a particular problem.
You should not waste the engineers time on textbook questions if you value yourself or the interviewee, and as the parent comment stated - the engineer should walk out if they start asking "basic" questions. Someone that worked in the industry for 10-15 years should not be bothered with them.