What is meant by the term ‘benefits realisation’ and why is this significant?

Benefits realisation:

Benefits realisation is the post-project operation of, and the procedure of managing a project, as like a new information system, therefore it maximise the chances of getting the benefits claimed into the business case. Each project must be followed, after an appropriate interval, by a post-project review, the most important aim of that must be to determine whether the expected advantages have been realised or not.