Application Deployment is a link between an application in inventory and an asset in inventory where that application is installed. You can set an environment label and one or more URLs for the deployment.
Why would you use application deployment?
If you are tracking both applications and assets (hosts) in inventory, then you may want to track where a given application is running. A deployment allows you to track that, along with some details about the deployment (environment type and URLs). It also makes it easy in the inventory pages to get from the application to the asset where it’s running, and vice-versa.
Application Deployments are totally different from Third-Party Product Deployments. It is possible to have an application that is linked to a third-party product and they can both have separate deployments. Application deployments track different things than third-party product deployments do. Your organization could use either or both type of deployment.