You can compare skills as your ticket into the working world. The more skills and competencies you have, the more opportunities you can get. Whether you are a full-time employee, a freelancer, or an entrepreneur, you need to keep sharpening the saw to stay ahead. With the hyper-competitive and volatile business world nowadays, having a lot of skillsets will ensure that you have a place to go should a crisis happens.
Unfortunately, many professionals keep on building the only skills useful for their current area of expertise. While this is good as it can make you an expert in one field, it would not hurt to develop general skills as well.