I'm actually certified in a version of SCRUM. I've been on a total of one project which did it in what I would say is the correct way. Where the primary purpose was to gauge work and plan around the developers capabilities and needs, instead of having deadlines imposed arbitrarily from the top. It worked great and we delivered a useful tool in a relatively quick period with pretty inexperienced devs.

Every other time though it's a poor excuse for managers to waste time with useless metrics reporting and whip the devs into coding faster.