Wayout is a daemon and must keep running for the output to be preserved. The call | wayout is an example to demonstrate it take its input from stdin. Wayout display things above the wallpaper. It is not an overlay that is present above other surfaces. If the pipe shut down, then the stdin is broken, and so Wayout shutdown.
I think what you can do is to prepare a fifo file that Wayout will read. You then can feed this file from outside, the way you want.
