One of the headline features for macOS Sierra was the Split View feature. It was first released in September 2016 and completely changed how you multitask on macOS. Earlier, there was no easy way to multitask on macOS unless you manually dragged the windows around.
This also wasted a lot of space on the screen since the dock and menu bar took up the areas at the top and bottom (or the sides if you place your dock there).
With a first-party split view feature, multitasking becomes much easier on macOS. You can have two windows open side by side and adjust how much space each window takes up. You can do this conveniently in full-screen mode without wasting space because of the dock and menu bar.
Before this, you could only enter Split View with the Spaces feature. The feature lets you create and switch between multiple desktops on your Mac.
These virtual desktops allow you to organize your application windows into numerous workspaces. You can still use multiple desktops and switch between them with the trackpad or the keyboard on macOS.
However, it isn’t as convenient as using the Split View feature. This feature reduces clutter, letting you focus only on two things simultaneously. It boosts productivity, too. Unfortunately,
Apple still does not allow you to snap your application windows, and you still cannot do that to enter split view. The feature also works for external monitor setups. It was the only real multitasking feature on macOS until the introduction of the Stage Manager in 2022.