I’m saying I don’t think sandbox is a noun, I think it’s a verb. I also don’t get why this is such an issue to you? A container simply is not a sandbox by itself. The collection of technologies that can sandbox can be used to sandbox a container, or an app running in a container, or whatever you want. A door lock isn’t security, a door lock is used to lock your door, which gives you part of a security strategy. Same principle.