For example, downloading the community edition lets you work with your cloud setup using your PC. You gain the efficiencies and speed that the PC environment provides.
In addition, using your local system for management means that you can potentially bypass some privacy and security issues that a cloud-based solution would present. Interestingly enough, the community edition is free (see the pricing guide), so you can try Scalr before you move on to one of the higher-priced versions.
You can use Scalr to manage the AWS (Amazon Web Services), Azure, and OpenStack cloud environments using a special engine that works by interpreting directives you create. This method of management means that you need to learn how to perform scripting tasks using the Scalr approach, but it also means that you can work with multiple cloud environments without necessarily having to learn each cloud environment's API individually.
Scalr provides training, but you can download the case studies, white papers, webinars, blog posts, and videos without having to buy anything. Of course, you can also view the documentation (as with any of the other products) if you have a strong interest in learning more.