It depends on the layout you’re going for. If everything on the page is going to have the same Container max-width, then just go with one Container stack. If you’re going to mix sections of content with different max-widths, or have some stacks you want to go edge-to-edge in the browser, you could mix and match multiple Containers. It all comes down to the page you’re building and what you’re trying to accomplish. This is why there is a Container stack instead of setting the max-width in the Control Center stack – more flexibility this way,
The Banner and Navigation Bar both have built-in ways to limit the width of their internal content.
Containers are specifically for limiting the width of content within them. When thinking about whether you need a Container just think “Do I need to limit the width of everything inside this stack?” If yes, then a Container stack can be used. If a stack like a Banner or Navigation Bar already has such a feature built-in you do not need a Container.