Here is my best explanation of what they actually are and why they matter: It takes effort to get AI to do exactly what you want. You want it to write a scope of works? First attempt - bad Give it feedback, missing context, incorrect instructions Second attempt - better More feedback, more context, include an example Third attempt - pretty good That cycle is annoying to go through everytime you prompt AI. So instead you do this once, capture what you have built as a re-usable skill Then everytime you get AI to write a scope of works, it will give you more consistent/better results