If you are responsible for Salesforce within your organisation, then you should without a doubt consider enrolling in the Salesforce University and getting Salesforce certified. Whether your remit is basic configuration, writing code or carrying out strategic business analysis, there is a certification that will benefit you you.
The value of the certification program is not that you learn about how to configure Salesforce, as that’s what the help pages are for. The true value is that it forces you to extend your knowledge of the platform and learn about features that you haven’t ever seen in action, or potentially didn’t even know existed.
If you have only every worked on one or two Salesforce systems, you are probably an expert in the features you use regular basis, but have a limited understanding of the platform's wide ranging capabilities. As you expand your knowledge of the platform, you will begin to spot opportunities to extend your organisation's use of Salesforce and deliver an increased ROI from the platform.
You don’t need to attend an expensive course to get certified either. There are plenty of free/cheap online resources to help you study. When I did most of my exams I used exam question flashcards, however you now have fantastic resources like Trailhead and Certified on Demand to get you up to speed.
However, as a Salesforce director indicates, Salesforce certification is really about helping admins, developers, architects and business users understand Salesforce holistically, and in the context of their businesses.