The argument for "everything-is-text" approach in Emacs interface is that the text is easy to work with and the possibilities are wide -- in this case for human

The argument for "everything-is-text" approach in Emacs interface is that the text is easy to work with and the possibilities are wide -- in this case for human. This is precisely the same argument for the choice of Lisp as a programming language the Emacs is based on -- the Lisp code is again easy to work with and gives a programmer lots of freedom, but it's easier for programs to work with S-expressions than text. In other words, in the realm of code, the equivalent of "text" is "data structure".