Optimize UI for using a tablet (iPad/Wacom) monitor

I find using an iPad Pro connected to a Mac using sidecar works great as a pressure sensitive tablet/monitor.

However, I also find that then the whole Photoshop UI is really hard to work with. I would bet those with dual monitor setups would benefit from a smarter setup. See the screenshot of what I'm using:

That's my main 32 inch monitor. Then I have to drag the photo editing window to the iPad. The nice thing is I can see everything at once. The not nice thing is it's all the same color, confusing and looks bad. 

My questions: what percentage of users use 2 monitors or an attached iPad or Wacom tablet/monitor? Is it worth offering an improved UI for them?