[tomsem]

Stage Manager enables at least one use case I'm experimenting with: I can resize the Kindle app window to make it a more comfortable size. In landscape orientation, single column is much too wide, and I don't care for 2 column mode. When in Stage Manager mode (on iPad Pro 12.9") I can make it about the size of iPad mini, which is what is to me more optimal (I turned off Dock and Recent Apps display). And having it more square (2/3 of screen) is pretty good as well.

And while I don't use my iPad Pro 12.9" in portrait very much, the same resize trick would again let you reduce line widths.

On iPadOS, there is not the fine grained resizing that you have with macOS: the app has to explicitly support given widths, so in the case Kindle app supports Split Screen modes, hence 1/3, 1/2, 2/3, 1 are available. They could add more in the future, of course. Apple Books seems to support some in between these as well.

I can do something similar with Split View, but it's ugly having 'something else' on the other side and having the Kindle app over on one side or other, not to mention the split bar and its handle.

And yes, still has 'affordance bug', though now it is the 'resize affordance' and not the 'home affordance'. And it's a little less annoying, being smaller and down in the corner.

(Continuous Scrolling mode, when available, also does not have issue with affordance.)