I think the primary use for layouts is for people that want complicated layouts of windows at startup that would be cumbersome to set up every time you log in.

I think in practice with as many workplaces as you like the most productive layouts on medium to small screens, which is to say most of them, is a number of workspaces each with a relatively simple layout and 1-3 windows only.

You can wrap the layout saving restoring functionality in a tiny bit of scripting to make it more useful on the fly. Basically the json isn't useful right from the rip because you have to manually uncomment whatever fields make a given window unique but a script can pretty much do that unless it requires a regex and window title to distinguish between 2 windows.