Here's an excerpt from the
xindy man page (boldface and italics in the original (formatted) source):
xindy is the formatter-independent command of xindy, the flexible indexing system. It takes a raw index as
input, and produces a merged, sorted and tagged index. Merging, sorting, and tagging is controlled by xindy
style files. ...
If you want to produce an index for LaTeX documents, the command texindy (1) is probably more of interest
for you. It is a wrapper for xindy that turns on many LaTeX conventions by default.
I interpret this as indicating that whereas xindy is (largely) formatter-independent, texindy is better suited for use with LaTeX documents since it knows about LaTeX's formatting-related and other conventions.
Of course, for sufficiently simple LaTeX documents and indexation requirements, the output of the two commands may well be indistinguishable. Not knowing how complicated your LaTeX document is, it's not possible to answer your question as to what "might go wrong" if you used
xindy instead of
For more information on the
texindy commands, see the respective man pages -- which can be brought up, say, via
texdoc xindy and