I was a mobile developer and worked on Windows Mobile and Windows CE (un-ironically called "WinCE" by Microsoft themselves) applications some twenty years ago. It was basically just Windows with a lot of unnecessary cruft stripped out. The basic UI was indeed absurd, with the standard Start menu and utterly dependent on the fucking stylus to work. But for applications it wasn't actually necessary to even use that shit. You could actually write applications that ran in kiosk mode and had nice big buttons so that users never had to deal with the Start menu or use the stylus at all. And in that mode it was actually extremely powerful -- you could do anything that you needed to do programmatically. I never once encountered a situation where something that I needed to do programmatically wasn't still available in the stripped-down WinCE API.