If you have two groups, and you accidentally start dragging a window (assuming you use the mouse at all, which I do) Hyprland will drag the entire group and merge it with the one it's hovering.
Now, imagine someone coming from Sway, who is used to rearranging individual windows by simply dragging them around without having to explicitly move them out of containers...
Same. It also has option to open an app when an empty workspace is opened. It's just so convenient compared to sway which is very solid but also feels quite limiting like i3.
I think you can open stuff when empty workspaces are created, I did it once but I do not anymore because my workspaces reason of being changes when I connect and external monitor.