On Tuesday, August 11, 2015, Magnus Manske <magnusmanske(a)googlemail.com>
Out of curiosity, was it ever used again after that
Yes. It was used a few months ago to prevent editing the Germany item on
Wikidata due to a very serious breaking issue. Also on several pages
following legal disputes.
Superprotect in my opinion if used correctly is an essential tool which can
prevent legal and technical issues that can in theory cause wide disruption.