I think the main point with Michel Lavaud's comment is not what you start
with, but the process of successive refinement:

  Clearly, different individuals will have different preferences in this
respect, and also the document will be passed along between different
persons in the publishing process, so there is the need for a good working
handshaking.

  A formula is a way of describing a logical structure, as opposed to a
picture, which describes a graphical structure (even though one may use
formulas to create pictures), so in this sense a music sheet can be viewed
as a formula, for example. So formulas are in much wider use that in just
math, and it is good for LaTeX, or any documentprocessing system, to
support that, mainly because it is costly not having the author entering
the formulas.

  So the ideal for the author, is probably to quickly output the semantic
contents, and it should be possible to somehow enter the other stuff
independently of this (also so that it is possible to choose a suitable
degree of integration of the involved processes).

  Hans Aberg