What is wrong with coding challenges? With a simple challenge you can get a hint of coding style (flashy vs pragmatic), accordance to current best practices, is

What is wrong with coding challenges? With a simple challenge you can get a hint of coding style (flashy vs pragmatic), accordance to current best practices, is TDD being used, clean code accordance and so on. And then you have something you can talk about in your final interview which can be helpful. Does the applicant take criticism well, can he explain his code or specific decisions etc.