I have made sitemaps for websites before because I had to. I didn’t quite think about it’s usefulness or the situations where it could be the most useful. So where can it be used?
Let’s face it. Not everyone understands why UX matters. You could be working in a tech company where you have to prove why you’re even there, to the development team, to the product consultants, to the marketing team and even to the stakeholders. Sitemaps lay down everything that there is to be built, and flowcharts represent the efficient way a user navigates using the system. By designing/building an efficient and effective sitemaps and flowcharts you can tell your development team that they have to create 3 pages instead of building 10 to accomplish a task. The product consultants would be thrilled to know that their users would be happy using the system that does their job quickly. To the marketing team ‘hey this is why our product is better than our competitors’ and to the stakeholders ‘we are gonna get you more money’.
What you do is going to help you reinforce your job and your position at a company. It helps to get others on to your side. Having said that, I had a hard time making a site map for a very dynamic website. Fortunately, the site had many static pages that I concentrated my sitemap on. But I conveniently let the dynamic part go unnoticed. I also did not clearly indicate duplicate pages. The site’s complexity did not give way for well-rounded site map. So it’s up to the designer to showcase what’s appropriate for a project; to foresee if sitemaps are important for a particular website.