Often also combined with degree program studies, to strengthen credentials in a professional area. Designed to be more accessible. Usually offered at Community Colleges. Often less stringent entry requirements. Takes care of most of the basic required classes for a Bachelor's degree program.
Completion gives a degree and a sense of accomplishment.
Credits can be applied to Bachelor's program, if taken at same college. Most credits will be transferable to other Bachelor's programs. Provides evidence to admissions counselors, employers, family and friends that you're able and willing to dedicate serious effort and time to completing further studies. Often used as a stepping stone to further education, as well as to gain credentials for specific vocations. With the advent of the internet, online learning is more widely available and increasingly popular.