Good question.

It's a pity the script used in the explanation didn't include "RECONFIGURE WITH OVERRIDE

GO" like the script in the question. The absence of the reconfigure statement after the sp_configure call has generated a message saying that reconfigure has to be used to give effect to the sp_configure arguments might suggest to some readers that this is the reason for the update statement failing, which it clearly isn't. In fact Bol suggests that the (first) RECONFIGURE command would fail anyway, and it would have been nice if the script in teh explanation had shown this failure.