An internship helps you develop an understanding of the world of work and an awareness of your own skills and abilities. Getting a good degree is vital but being able to demonstrate to an employer that you have a wide variety of other skills will improve your employment prospects.
In the current economic climate, employers are looking for relevant experience which backs up your academic abilities and demonstrates your 'soft skills'. Work experience highlights to employers that you have some understanding of what it’s like to work and that you will have gained some of the basic employability skills they want.
Competition for jobs means that you need a way to stand out. As well as helping you learn essential skills, work experience can set you apart from other applicants when you start applying for jobs. Everyone's experience is individual to them, so highlighting what is unique about your experience can help you stand out.