I never understood the rationale for Wayland's "security"... All the programs that I use (ls, rm, vim, ...) can "spy" to each other, and have unrestricted read

I never understood the rationale for Wayland's "security"... All the programs that I use (ls, rm, vim, ...) can "spy" to each other, and have unrestricted read/write access to all the bytes in my home directory. That's the whole point: I run these programs to control said bytes. What's so special about the pixels of my screen that the programs that manipulate them need to be protected from each other? If anything, the pixels in my screen seem less critical to security that the bytes in my disk. But Wayland insists in making that difficult, for incomprehensible reasons. Those are my pixels and I want to do what I decide, not what Wayland lets me to. I control my programs, not the other way round. If I decide that this program reads one pixel on my whole screen, or the global mouse position, or whatever, I see no point in forbidding me to do it. Of course, if I want to run some rogue program whose author I don't trust, I will do so inside a limited container. But this has nothing to do with graphical applications. I wouldn't like the rogue program to read my homedir either.