I don't disagree that the ability to select notice placement is a good thing (and I love Teams -- best new product MS has released since Excel), but it does feel like different groups within MS still fighting each other instead of working together: Windows has a notification center. Ideally, ALL notices would use that for a consistent experience. Consistency is the single most important feature of a good UI. The proper solution here would have been for the Teams team within MS to push and work with the OS team to add this option to the system-wide notifications and still worked within that system. Then, everything would benefit and remain a cohesive UI. Instead, this just creates a one-off fix that further creates a chaotic feeling to using Windows.
If the Windows team said they couldn't do this for whatever reason (design reasons, lack of time, etc.), then Teams should offer an option to use the System Notifications or custom. That way, at least by default, it would continue to use the OS notification center, but users desperate to move at least Teams notices could do so. By the picture in the article, doesn't look like using the Windows Notification Center is even an option. That's bad.