There is a fairly straightforward reason why
Microsoft Word has no "show codes" feature - the Word file format
doesn't have codes (in any meaningful fashion) to reveal. Unlike
inline document formats -
SGML in all its variants,
WordPerfect,
XYwrite,
Locoscript,
View for the
BBC Micro,
RTF, whatever - where formatting is marked by
control characters embedded in the text to indicate a format change at that particular point, the native Word format maintains (simplistically described) a complete version of the text without codes, preceded by a separate binary section containing arbitrarily ordered pointers to variously formatted bits of that text.
This is clearly a programming decision for the programmers' benefit, which is not designed to facilitate users' poking around in the innards of the file (you can screw up a Word file completely much more readily than many of the others mentioned); it makes it easier to deal with multiple levels of undo and allows the loathsome "fast save" option (which is a good way of promoting catastrophic data loss) where new bits of the text are just tacked on at the end of the file). Word does have the facility to display non-printing characters - carriage returns, tabs, spaces, soft hyphens and the like - which is reasonably useful - but will not and cannot show an annotated, non-WYSIWYG version of the text with interspersed character/paragraph/page formatting codes. As to whether it's a good programming decision ...