Universal Control: Check out how it works

With Universal Control, Apple has succeeded with a new productivity feature that should help users save plenty of time, especially for users who own more than a single Apple device. Beginning with iOS 15, iPadOS 15, and macOS Monterey, a mouse or trackpad on a single device can be used with all other devices simultaneously.
The only prerequisite is this: all devices will have to be logged in using the same Apple ID via iCloud with the Handoff function activated.
To check out how this new feature functions, here's a short video from the WWDC21 keynote that sheds additional light.
I'm really not seeing the practical use. Will this die like 3d touch navigation? Hyped in all the reviews, dead in actual use.