Re: Nope
With X11 I can set up a login, and with some care, set up a shell that uses DISPLAY to run an X11 application in the context of THAT user, and by use of ssh with a cert, NOT have top enter a password.
That way you can (for example) sandbox everything you do with a web browser within that login TO that login. If web site 'a' tracks you, you can completely sandbox your history etc. JUST to that login. You can ignore using NoScript for THAT login, and things work, and maybe even (with firefox) have it PURGE HISTORY on exit.
As an example I need to use slack for work. So, the slack login has its own Firefox with its own history etc. allowing script and completely separate from anything ELSE I might do.
And also, if you work on embedded stuff, you can run an editor on the embedded platform (running Linux, let's say) and by setting DISPLAY you can use your desktop for an editor like 'pluma' or the 'meld' application or one of many OTHER useful GUI-based programming tools. Good luck doing that with WAYLAND. [I have heard about the workarounds. No thanks]