It was uncommented in the new one by accident. The main reason it is intended to be commented out by default is because in some environments it would cause an error if those settings are locked down at a higher level so we were just trying to avoid an error that could crash the site in some environments.
It is a very useful setting to uncomment because it affects how large of files can be uploaded, this settings is discussed in the article Supporting Large File Uploads.
So if it causes you no errors (and it should cause none in most environments) then that is good.
Best,
Joe