As few comments already mentioned, post college, preparing for this type of thing immensely helps in job interviews. I find it very hard to clear job interviews and in 2017 alone, I appeared for ~25 job interviews. I'm very convinced that competitive programming skills gives you a leg up in job interviews.
Many people may already may know this, but Peter Norvig indicated that it correlates poorly with on the job performance (at least at Google) [1]. I wonder why, then, companies still continue to do this style of interviews.