Especially in the communications area, it is important to have a portfolio, not only to give examples of your work, but to show how you communicate it. In a certain way, it's selling or marketing your work, but in a more professional and illustrative way. Instead of talking about your experience, whether in person or in your C.V., you actually demonstrate your accomplishments.
If you put a good amount of effort in doing your portfolio, it will show; and that is always a wanted quality. Having a portfolio ready is not very difficult to do, and it will surely give you many benefits.