Stage Manager was originally meant for the Mac… the idea behind it is to help with window management, but if you don’t need that kind of assistance. Then perhaps, you could find it useless. Craig Federighi did an interview explaining how his son had so many windows off to the side disorganized… introducing Stage Manager was the reason for this.For multitasking, I would not compare Stage Manager on an iPad to Stage Manager on a Mac. I find Stage Manager on a Mac completely useless and turned it off after the first day. In MacOS, Stage Manager is a poor substitute for the functionality of the basic MacOS floating windows environment that makes working on multiple documents and spreadsheets so easy.
To be clear, all of the above is caveated by "for me" or "in my experience". YMMV.
It’s true, floating window environment already existed on macOS… but Stage Manager on the Mac has a different purpose. It’s meant to help with organization whereas on the iPad it’s meant to bring an increased level of multitasking.