One of the best new features is Catalina is Sidecar, the wired or wireless connection that turns an iPad into a second display for Mac. It lets you multi-screen on a desk or use an iPad and Apple Pencil as a Wacom-style input device for artists.
There have been third party products that allowed both previously, but this is the first time Apple has decided to support the feature natively within macOS. We’ve tried it, and it’s superb.
Screen Time is also now on the Mac, following Night Shift from iPhone and iPad to Apple’s laptops and desktops. Sure, you probably need to be on your Mac all day for work, but it’s nice to know just how much time you spend on all your devices.
There are some welcome behind the scenes changes too, like the ability to find offline devices in the Find My app along with tweaks to core apps like Mail and Safari.