I will wait until this ships, but I don't think that I will like it more than quickly switching apps with a sideways swipe. For example: I write a lot on my iPad, keeping a text editor open to a markdown file and a PDF open in an adjacent app. I sometimes quickly swipe back and forth when making edits.

I recently bought a keyboard cover for my iPad, which I don't often use, but an iPad Air with a keyboard cover overlaps some laptop use cases, and the split screen might be useful.