It's interesting you'd use jekyll server rather than just to generating static pages. If I wasn't just using an engine server anyway I could see the appeal of hugo.
I don't use the server. It's just when you are working on a static site it's nice to have it constantly update. Hence the server. Hugo auto-reloads the page every time you save. Makes for a good experience to preview what you are doing. Suppose you could use a specific Markdown editor instead to preview the changes.