If you are great at organizing windows... then you really won't see the benefit of Stage Manager on macOS.
It's a combination of emotions. Some are disappointed that Stage Manager isn't on 2018/2020 iPad Pro models, some just wanted macOS-like experience when it comes to window management. But Apple decided to take a different approach when it comes to resizing windows which wasn’t expected.
And Stage Manager being off by default is a factor it being a drastic different to how users normally interact with their iPad. It would be such an alarming response if as soon as iPad user updated to iPadOS 16 and they see Stage Manager on the screen. But I’m sure Apple will give them splash screens educating them on the new feature.
There’s chapters available. So, you can skip to Stage Manager section.