User blog comment:Rappy 4187/Technical Update: November 30, 2015/@comment-11733175-20151201085517

Seeing as the template namespace is protected, it seems sensible to protect modules as well otherwise the code that vandals might change is still vulnerable.

The sidebar module seems a bit useless on some wikis. For example RuneScape Wiki does not use Portable Infoboxes as they don't have the features we need for them to be viable at the point in time. this results in lots of non-portable infoboxes and thousands of pages without an infobox (according to insights anyway). Flags are also unused as they provide no obvious benefit at this point in time. Which leaves template classification which is still very new, is not particularly easy to do en masse, which it needs to be if this is ever going to be picked up by large wikis, and has no benefits at time of writing, same as flags.