A comprehensive process map/workstream is an incredible tool for increasing efficiency, decreasing costs, understanding areas of opportunities, and identifying/mitigating risks. Businesses of any size can benefit from process maps. I've used process maps in different scenarios: process improvement initatives, project implementation/executation, and even used it as supplement documentation to job aides, policies/procedures, etc. My favorite approach to process mapping is identifying current state, using controls to identify areas of opportunities, then developing an improved future-state.