There’s a lot more to an application than its configuration. It may require certain specific system libraries, need a certain way of starting up, or a whole host of other special things. With a container, the app dev can precreate a perfect environment for their program and save you LOADS of hassle trying to set it up.
The benefit of all this is that you can know exactly where application state is stored, know that you’re running the app in it’s right environment, and it becomes turbo easy to install updates, or roll back if needed.
Totally spin up a VM, install docker on it, and deploy 2-3 web apps. You’ll notice that you use the same way of configuring them, starting and stopping them, and you might not want to look back ;)
Glass cups work unfailingly for me. As far as I know they don’t see very well, so once, I tried slowly lowering one over them, and have been doing it since. Nothing else needed, just wait for it to land near you on a hard and even surface. They so far have not noticed it until the cup was fully down. After catching one, I slide a thin paper/something under the cup, and take the whole thing outside to release it.