Depends on the journal you're publishing in.

Lots of journals (at least in my biological sciences field) require you to submit your code along with your publication so that a) the editor can repeat your results to accept your publication and b) for other scientists to repeat your stuff. Biostatistics AFAIK has an editor responsible solely for reproduction of results.

Personally saying lots of my code is repeatedly re-used by colleagues who can't program, for example scripts that parse BLAST-output and get the best result for each query etc.