I was asking because we build a product that is deployed at customer site, so deployments would not be useful for that. But, we do deploy our own product to test environments for manual testing. (We also have automatic testing, but thats per commit and removed after testing... so not relevant here.)
We have the following branches (simplified): master release-4.2.x release-5.0.x release-5.1.x
Now, I was thinking to use the deployments feature to track the deployment of the test environment of each branch. So our testers can see the status of their test environment.