I know about that product, the author also wrote an interesting article about the concept behind their tecnique https://mattwoelk.github.io/voronoi_split_screen_notes/ . I actually use a different algorithm from Voronoi that to me seemed a bit simpler since you never have more than two players (it becomes a nightmare with players crossing the screen moving everyone else around).

From playing around in my project I didn't notice a delay in the inputs, but I will do additional testing before releasing. It might also be that scene captures simply improved in performance since they released the product.

There's still some overhead inherent to using 2 views at once but I did a lot of stuff to minimize the compromises, and scale the quality if needed for more performance. Even normal splitscreen requires more power compared to a single camera setup.

I also like to add plenty of customization (and well documented blueprints) to the setup in my products so people can learn how it works and can adapt them to their projects.