The correct question is "Do you plan on disabling your account more than once and thus need to have the process automated down to a single button push?". That is how this is a "one-time deal".
Of course, having a single button push to disable your account sounds like a really stupid feature. You could make it less stupid by adding an "Are you sure?" prompt. And who am I to tell you exactly how you want to leave your disabled account? It would be better to let you pick which items you want to blank out or replace with alternates as part of the process. Since implementing an "are you sure?" dialogue seems hardly worth the effort for such a can-only-be-used-once feature, we'll just require you to declare your intention twice before you submit.
So I've collected the most commonly desired-to-be-blanked fields on a single form. Simply enter "0" twice to indicate that you are sure you want to disable your account and press the one button. All implemented. Now we just lack some documentation updates.