Depends on my use case.
I have the 14" Mac Book Pro (M1 Pro) and I disabled it when I'm mobile. I'm usually just focusing on one task at a time in a coffee shop. Be that responding to emails. Online shopping. Social Networking. Creating Music.
However, in clamshell mode at home, I can't live without Stage Manager now. It's a god send for multitasking. Didn't think it would be. But then I didn't go into with any preconceptions. Just switched it on and it got out of my way.
It does help with the fact I have an ultra wide monitor. If I owned a standard 16:9, 16:10 monitor, then I most likely would feel the same as I did when I'm using the 14" screen on the MacBook.
But even if you cover up the icons on the left, you can still see them, exactly the same way you see the dock (if you have auto hide enabled).
So I don't see the issue that people are having with it. To be honest, it's much quicker than going down to the dock, or using a keyboard shortcut because it's much more visual, and so the brain is able to go to exactly what it wants without the mental load.
Just my opinion, by the way, and I'm a bit of a nutcase in life. So, there's that to consider before you get angry at me about my views.