The code challenge and take home assignment is too save our own time during interviewing candidates. We have pet to feed, we have family to take care, and daily tasks to work just the same as the candidates. We hire one of our senior management teammates just after a face to face whiteboarding design session, but not everyone can present decently during f2f, we use it as a second chance. Never forget the interviewers also take time to review and provide feedback to candidate’s work.