I think that's a great way of interviewing! But don't you fear this only works for smaller companies? Imagine some company like Google or Facebook would do that: I would expect people to just start learning answers by heart..
People more or less memorize a subset of leetcode and CTCI solutions and the bullet points from various scalable architecture books and resources, all of which are provided by recruiters in their email conversations with candidates. Fresh grads, the affluent, and people who have few or no social obligations (e.g. family) spend a few weeks (or months) doing what amounts to cramming for a test to prepare for these things.