this type of stuff is generally for interviews. But it does tell you that the candidate has learned the patterns in question. That particular solution isn't important, but knowing good design patterns to solutions is. Knowing how a decent number of problems are best solves gives them a good intuition of how to tackle problems. Otherwise, they would tackle it using their intuition/vibes. There are books one can read to learn this stuff as well I'm sure, but how do you prove what knowledge you've retained?

10 programmers will write 10 different ways to solve a simple problem. and that code is tech-debt other programmers have to maintain at some point. Just having coders that have the same base-level memorized problem solving patterns can ease that pain, and it can make collaboration/reviews easier down the road.